351W Buildup

[JimG]

Not sure yet if I'm just going to band-aid my motor, (blew starboard head gasket), or pull it and go through it.

I might pull it out, and freshen everything up since I really don't know what I have. I've been happy with the performance, 53mph @ 5k rpm with Ultra prop, but while it's out...

The former owner told me the short-block had been replaced, but the heads and cam were from the original Holman Moody motor. Aren't the HM cams supposed to be pretty good?

What heads did HM use on the 351? I'll be checking for a casting number when I get them off.

While the motor is out, I'm going to polish the exhaust logs and risers, and repaint everything. And repaint the bilge, reroute some wires, etc. I've looked at some of your bilge pics, and they look great! I want mine to look like that!

Any suggestions?

Thanks guys!

Jim

[Team Jefe]

No real advice, but I'm always ready to help pull the motor and turn wrenches.

I do say do the whole motor, you can afford to and have the palce to do it.

[Jraysray]

I don't know much, but more than willing to give you a hand. Hey, no better way to learn than on someone elses machine, right?:wrench:




Not sure yet if I'm just going to band-aid my motor, (blew starboard head gasket), or pull it and go through it.

I might pull it out, and freshen everything up since I really don't know what I have. I've been happy with the performance, 53mph @ 5k rpm with Ultra prop, but while it's out...

The former owner told me the short-block had been replaced, but the heads and cam were from the original Holman Moody motor. Aren't the HM cams supposed to be pretty good?

What heads did HM use on the 351? I'll be checking for a casting number when I get them off.

While the motor is out, I'm going to polish the exhaust logs and risers, and repaint everything. And repaint the bilge, reroute some wires, etc. I've looked at some of your bilge pics, and they look great! I want mine to look like that!

Any suggestions?

Thanks guys!

Jim

[JimG]

Thanks guys!! :yes:

[Cuda]

I don't remember any specifics, but I had a 351W in my 69 Mach I and it ran like a raped ape.

[DonziNUTS]

I am currently rebuilding my 351W. Found master rebuild kits from 310 up to the sky! The $310 includes cam and lifters! Shop around...if no machining is required..it well worth rebuilding while it's out. I will keep posted on how much I spend...will be putting together in the next week or two.

[JimG]

Donzinuts, tell about your rebuild... what cam are you using, what are you doing to your heads? Was your 351 a HM motor?

Thanks a ton!

Jim

[JimG]

Some of you other HM guys, what did you do to your motor when it came out? I could really use some ideas, and you guys are the experts!

Rick, the former owner of that gorgeous GT-21 twin, dynoed his 351w's at 350hp. What cam, intake, etc did he use? Does anyone know?

Thanks very much guys! I look forward to your input.

Jim

[Craig S]

fwiw, Popular Hot Rodding just had a build up series. Several builders were getting north of 650hp on street application windsors.

[JimG]

Thanks Craig, there's tons of good info on street SBF's out there. Some of those guys are spinning to 6500 rpm! What's tough is finding info on building a marine Ford. I don't want a monster, just reliable 2000-5000rpm power. There's been lots of them built by board members, I've been searching the threads, but the info is spotty.

I'm hoping some of them, Mattyboy, Rick, BigGrizzly, Moody, Forrest, Tony, Boldts, etc, will chime in with suggestions... Thanks!!!

[turbo2256]

Send me the heads and I will port them for ya its the biggest and only mod you will need other than fine tuning. I would compair it to a 150 shot NOS system in power. With out the NOS issues. Some pics of my 436 HP @ 6000 RPM 302 with 69 351W heads ported. see thread my latest engine pics

[Rootsy]

building a 351W is going to run right along hte same lines as building a 350 chevy... BUT your cylinder heads are going to be BY FAR your greatest restriction to making power. much more so than with most stock chevy heads on a chebby.

the newer GT40P heads are a good alternative to the stock if you don't want to get into the porting game. A LOT of aftermarket heads out there too, especially from the likes of world products, AFR, TFS, etc etc etc... But for saltwater i reckon the comfort zone is with iron for sure and that pretty much leaves you with the windsor and windsor jr heads... or if you can find em still the Pro-Action Windsor heads which i had heard were pretty darn good...

Fords tend to differ from sbc's in that they run a lot more valve lift. most of this has to do with combustion chamber sizes and volumes and valve diameters and port volumes. any stock ford head will benefit from even the slightest bowl porting, installation of larger valves, a good valvejob, port matching and some blending...

to give anyone some "rough" ideas of what a camshaft will do i can run a combination through desktop dyno 2003... but i need very accurate information about the engine, especially cylinder head flow numbers.

JR

[turbo2256]

GT 40 heads are better than the P heads the spark plug location in the P hurts air flow across the combustion chamber. In either case assuming you only want to turn close to 5200 RPM the ported 69 351 w heads will put out more power in a boat and actually flow more air than the GT 40 heads.

[Rootsy]

GT 40 heads are better than the P heads the spark plug location in the P hurts air flow across the combustion chamber. In either case assuming you only want to turn close to 5200 RPM the ported 69 351 w heads will put out more power in a boat and actually flow more air than the GT 40 heads.


Turbo,

what exactly are you doing to your 351 heads and what kind of numbers are you getting? valve sizes too please... i want some future reference for projects...

Root

[turbo2256]

I have the GT 40 valves in this particular engine 1.94 int 1.6 exh. Air flow is 235 at .5 lift not fully CNCed so there is more avalable. It is around a 3 cc port volume increase over stock to keep the air speed up and RPMs down. E7 heads we do are pulling around 217 to 220 at .5 lift with 1.84 valves. We have missplaced most of our Ford flow data sheets as I locate or do some more Ford stuff I will be posting it on this web site http://users.erols.com/srweiss/ . Click on cyl head flow data updated. I have posted data for some BBC, SBC, BBF FE, 351C, and Modular eng cylinder head flows look for the ones showing "ported by BHPerformance". If you havent been to this sight before look around he has most of the stuff needed to figure HP etc as well as a great data base. I figure my HP now based on air flow only from his site cuz its all done for you and is much more accurate than the programs I have used. We are also excited about a new CNC program we are tweeking and will be marketing soon and as we have new heads to port will be improving flow over our past efforts with lessons learned and the new software.

[turbo2256]

By the way ROOTSY I was in your area last week is it J & J Western shop near Town and Country bike dealer. Any way bought a pair of boots and gloves there.

[Rootsy]

you were literally about 3 1/2 miles from my home...

JR

[JimG]

I'm going to pull the heads this weekend, most likely. What head castings am I looking for? Are some stock iron heads better than others? How about the HM cam?

[Moody Blu']

turbo i sent you a PM

Thats what i heard abotu the stock ford heads also, you can make them just as good as most the aftermarket heads out there,AND THERE IRON!

hey jim what size ultra do you have on your boat?

Im running a 24x 15 elephant ear prop and i get 5100 rpm's 51mph GPS I have bottom paint on her too.I dont knwo if that will help you gauge your boat? perhaps if you odnt have bottom paint youd be higher? Anyhow, im running a custom ground lunati cam that falls in the area of the 00110 model http://www.holley.com/HiOctn/ProdLine/Products/IEC/IECC/Ford5.html (under marine). I run a edelbrock rpm intake, msd 6t ignition accel coil msd distributor and a edelbrock 750 ford motorsport 9mm stainless connection racing wires. I USE to have log style headers, I now have a full TRUE stainless HEADER exhaust from hi tek out of australia. thats about 30 extra hp.(I wasnt to pleased with having to use spacers for this exhaust but its all bolted up now)

I shotpeened the rods, balanced and blue printed the bottom end. it runs real strong 24/7 my next step is to send out my spare 351w heads and have them ported. since i have a full header exhaust now the heads will not be restricted and the fear of reversion is gone!(I hope)

also, the stock ford valve train isnt good for anything over 5000 RPM unless you go with a aftermarket valve train, something like a ford motorsport 1.6 ratio roller rocker (that will be the valve train i would use if i had my heads ported)

[turbo2256]

Ok here is a 351W build up. 351cu in set up for 5200 RPM max power will produce 442 HP with these mods. For a 351 use the 351 marine heads if possible most of these use the older style 69 to 70 351W ports. Only 215 CFM is needed. 351 heads will come in around 230/235 CFM with the 1.94/1.6 SS valves. I would recomend inconel exhaust valves for marine use with this power out put. If your planing on boosting inconel exhaust is a must. Cam choice would be around 220 @ .050 lift, around .500 max lift as close to 112 degree lobe centers as possible. Some form of performance exhaust is needed. As far as an intake goes a Vctor jr will restrict the air flow to around 215 at .5 lift with a port match. A Torqer II will work but with out fully porting it your going to loose some HP. My choce would be a ported Torker II because of the smaller plenum volume. I know hatch clearance could be the driving issue towards the Torqer. A dual plane will only flow around 160 CFM so I wouldnt even conceder that option. Porting a dual plane is a real pain.

[Rootsy]

Porting a dual plane is a real pain.

PITA to port yes... but extrudehone is an option... doesn't mean that it is fully optomized though... for all the little tricks to bump flow in the direction you'd like it... but it does remove restrictions and balance the runners fairly well... done any flow testing with this?

Root

[JimG]

Turbo and Moody, great info!

I'm not looking for much, and am retaining my Edelbrock log manifolds. I know that will limit my potential. I'd like to retain the HM cam, too. I'd try a different intake, (mine looks crappy), but I'm also tickled with my Edelbrock 600cfm carb.

I'm not necessarily looking for more speed out of this boat, just reliability. (This is my wife's boat, she drive it more than me.)

Moody, I'm running a 23" Ultra, (22 with an inch added). It's like magic on this boat. Torque steer gone, instant holeshot, great cruise, best top speed. Whatever you have to do, (beg/steal/murder) get one. I balked for a long time, thinking, "What can be so different about this prop?"
Until I put it on.... :yes: :yes: Janet will not drive it with an aluminum prop, after she felt the Ultra. It's that different.

Does anyone know the cam specs on the HM?

Thanks guys!

Jim

[turbo2256]

We have not had a chance to flow any extrude honed stuff. We have called and talked to them. They wont give any flow numbers for their work last I looked they woun't advertize any. There prices are quite high 400 to 600 easy our prices for porting intakes and flowing them bolted to your heads is around 175 to 250. They will send you back your stuff with no flow bench testing. I would use their process with like Ford upper intakes and such that are impossibe to get into with out cutting them open (which we have done). Still for 600 bucks I would look at all other options first. We even looked into purchasing there equipment its very expensive they only lease and they are the only source for the abrasive medium ther e price was quite a few K a month.

[turbo2256]

Turbo and Moody, great info!

I'm not looking for much, and am retaining my Edelbrock log manifolds. I know that will limit my potential. I'd like to retain the HM cam, too. I'd try a different intake, (mine looks crappy), but I'm also tickled with my Edelbrock 600cfm carb.

I'm not necessarily looking for more speed out of this boat, just reliability. (This is my wife's boat, she drive it more than me.)

Moody, I'm running a 23" Ultra, (22 with an inch added). It's like magic on this boat. Torque steer gone, instant holeshot, great cruise, best top speed. Whatever you have to do, (beg/steal/murder) get one. I balked for a long time, thinking, "What can be so different about this prop?"
Until I put it on.... :yes: :yes: Janet will not drive it with an aluminum prop, after she felt the Ultra. It's that different.

Does anyone know the cam specs on the HM?

Thanks guys!

Jim

The build up I just mentioned would be a very reliable package that should run for years without issues since nothing is being over stressed. If you are looking for a bump in power and wish to retain most of what you already have pocket porting your existing heads is a great improvement cost is closer to 200 this would put you in the out of the box Torqer II manifold area. From past experance a 585 BG is a good size carb for either of these combos a 600 Holley or Edelbrock will also work.

[turbo2256]

As for adding a blower a low boost 4 lbs application would boost the power to 562 HP 8 lbs to 682 HP with a turbo a roots style or centrifical blower I would estmate 512 at 4 lbs and closer to 590 at 8 lbs. Compression would need to be close to 8.5 for this.

[Moody Blu']

As for adding a blower a low boost 4 lbs application would boost the power to 562 HP 8 lbs to 682 HP with a turbo a roots style or centrifical blower I would estmate 512 at 4 lbs and closer to 590 at 8 lbs. Compression would need to be close to 8.5 for this.

do you have any leads for me for a marine blower on my 351w?

[Moody Blu']

Turbo and Moody, great info!

I'm not looking for much, and am retaining my Edelbrock log manifolds. I know that will limit my potential. I'd like to retain the HM cam, too. I'd try a different intake, (mine looks crappy), but I'm also tickled with my Edelbrock 600cfm carb.

I'm not necessarily looking for more speed out of this boat, just reliability. (This is my wife's boat, she drive it more than me.)

Moody, I'm running a 23" Ultra, (22 with an inch added). It's like magic on this boat. Torque steer gone, instant holeshot, great cruise, best top speed. Whatever you have to do, (beg/steal/murder) get one. I balked for a long time, thinking, "What can be so different about this prop?"
Until I put it on.... :yes: :yes: Janet will not drive it with an aluminum prop, after she felt the Ultra. It's that different.

Does anyone know the cam specs on the HM?

Thanks guys!

Jim\

Bro, I have a 26x14 1/2 volvo ultra waiting to be put on :cool!: I figure the headers i installed will give me the ponies to push the motor to around 5000-5200 with the added pitch on the prop. finally. Im also taking off the botttom paint and putting a special ultra smooth coating on the hull.hopefully ill see the 60's

[mattyboy]

Jim,
I'm not a real good wrench guy and can't comment on rebuilds or parts but I would pull the engine and go thru it, I mean yes just fix the immediate problem if you're looking to salvage the season ( yes i know you have a long season in TX) but if you have time do it right what would be worse than fixing one head then having the other go??
I took care of some things i had the $$$ for when WE had the deck off but I had the time just not the $$$$ to go all the way

Moody real interested if headers do enuff to spin 2 more inches of pitch the same rpms as you do now???

[DonziNUTS]

I have a quick question...these types of numbers with just head work...what are you doing to the bottom end? If you are getting those kind of numbers with just head work I am interested in doing my 18 with a 351w. Can you give some info about bottom end?

[JimG]

Thanks Matty! At the very minimum, both heads are coming off. I'll have them 'fluxed, and reworked. Possibly change intake manifold. I'm going to look into Turbo's head mod, but will most likely retain the HM cam. Still don't have anyone to tell me the HM cam specs. But I guess it's ok.

Jim

[mattyboy]

Jim,
i have some original h/m paper work on my 351 maybe there's some cam info on it

[turbo2256]

I have a quick question...these types of numbers with just head work...what are you doing to the bottom end? If you are getting those kind of numbers with just head work I am interested in doing my 18 with a 351w. Can you give some info about bottom end?

I use the highest quality ARP fasteners. Studs for the heads and mains, their best rod bolts, pistons should be forged, crank inspected, hardened, straightened and pollished. premium rings file fitted, premium bearings, some mods to the oiling system and ballance.

Aftermarket rods, cranks, etc can be used if you got the bucks. Using the heads to aquire most of the HP and matching all the parts and keeping it at 5200 RPM dosent stress the componets as much N/A or low boost applications 4 lbs.
If your prone to driving full throttle all the time you should concider the better bottom end componets, 8 lbs boost more.

[turbo2256]

Thanks Matty! At the very minimum, both heads are coming off. I'll have them 'fluxed, and reworked. Possibly change intake manifold. I'm going to look into Turbo's head mod, but will most likely retain the HM cam. Still don't have anyone to tell me the HM cam specs. But I guess it's ok.

Jim
I probably could almost guess at the cam being the hyd version of the 289 hypo cam but not shure. At any rate our port work increases air flow through out the lift range .1, .2, .3, .4, .5, etc so even if your only at .450 lift your going to see a big improvement. Knowing the lift we can even bias air flow some.

[boldts]

The best source for information is usually the source itself. Jim, back when I had my 69 18' Classic, it did not have the original block, but did have all the H/M accessories. Holman Moody used to be in the Charolette, NC area. I'm not sure if they are still in buisness as I've read and heard that they were now only doing restoration work of H/M cars.

Many years ago, I called their establishment and talked to Mr. Holman about what I would need to duplicate a H/M 302 Ford engine for my Donzi. Being that I was inquiring about a boat instead of the usual car, he was very acceptable to my questions and we talked about the boats for what seemed to me at time eternity. Bad news he had for me was that all of the machine dies for the parts had been destroyed. He flat out told me that unless I had more money than I knew what to do with, restoring an engine to a H/M original would be so costly, I was better off finding a aftermarket replacement engine. Most all the companies available today can come up with an engine that with the correct parts to work in a marine enviorment. It's all about torque in a marine engine or so I've been told.

It's been so long, I can't remember now, but I believe H/M was using the 351 Cleveland heads on their small block Fords. The biggest problem with the SB Ford is the air flow through the heads as been mentioned here already.

Best thing I can suggest is try contacting the Holman Moody location and see if maybe someone there can tell you what was used in the 60's engines. You'll notice that there are still H/M parts available, but...... they are very expensive and primarily, the biggest reason I did not follow up on putting a H/M engine back in my Donzi. They have a parts listing that includes a few of the parts used in their engines including cam grinds. Yes, I wanted a set of those H/M valve covers and a new H/M intake too.....that is until he told me how much I would need to pay! Another thing that you should keep in mind is the water your using your Donzi in. My boat was fresh water only except for a trip to Sota 1 year for the Rally. Truthfully, I'm not the one to ask about salt water effects on engine parts. All I know is it can be H*** on the electrical parts back in the engine bay. Been there, done that.

Here is their website:

http://www.holmanmoody.com

[mattyboy]

jim,
i did as boldts said i contacted h/m i'll keep you posted

[Moody Blu']

Moody real interested if headers do enuff to spin 2 more inches of pitch the same rpms as you do now???

matty im confident the headers will turn the 26p prop, they are custom made, all headers are equal length. there equivalent to a quality full header system for a car. there set up for top end also, mine are the first with a 4" outer and 3" inner. all the others hi -tek has made were 3" outer 2" inner. thats why i had a valve cover problem, because alan didnt compensate for the larger exit pipes :o . Im not to happy about the spacers but it is still a quality product. I will let everyone know. I will be picking up dr dans trailer for my donzi so i may splash it in greenwood lake in spring to test em. I do need to do a deck off for my 20 gal tank.(need help) I may just replace it with a 20 gallon and install 2 10 gallon tanks on port and starbord side in the back for more weight in the rear to get the nose out of the water. not sure yet. i did think about running one 10 gal dry and be leaning to a side, maybe i can suck out of both tanks at the same time?

we shall see.

[Moody Blu']

jim does your boat have bottom paint or what?

[mattyboy]

blue,
you loose 400 rpms on the 26 but pick up maybe 200 on the smaler dia. i think you'll be at around 48-4900 which is fine don't think headers are gonna give that much more hp

[JimG]

No bottom paint on mine.

[Moody Blu']

No bottom paint on mine.

a ha, so what that tells me is that a t 51 mph on gps at 5100 rpms I have a fair amount of power with bottom paint give it 4-5. exagerated, 7-10 mph without bottom paint.

matty. i figured somewhere around there. maybe 5000rpm 5100 pushin it, but that should be a fun ride !!

[mattyboy]

Moody don't forget to factor in the aerodynamic drag of the hood scoop ;p

[BigGrizzly]

Whel Here I am. H&M used Three versions of 351 engines.!) the Winsor which was prety much close to the stock Ford with a nice came with tons of mid range. The water pump was mounted on the cramk with a cuppler similar to thoes used o a log splitter. the circ pump wad discarded ant a cross over was welded to a plat that took place of the waterpump. Then the nect was a Cleavland engiiine that had big ports and 2.19 intake valves with a special intake manifold with giant ports. They only made about 250 of intakes and were also used on the pantera's. Then the most common Clevland used on Donzis was the big port head with open chambers(lo compression) and beleave it or not small valves of the 2.02 intake and 1.6?? exhaust valves. I have each of these combinations and have tested all of them with no less then 8 different cams combinations. One thing that I have found is that within 20->25 horse power my 18 Corsican's top speed doesn't change but 1 MPH. I now run the stock type 351M, heads which never put into a H&M boat engine, with a Babe Erson Max 108 cam. the only set of CMI hedders ever built for this engine and sounds better than my blown Criterion.
Jim What I would do,is put it back together with the same configuration, find a good set of exhaust and spend the extra money the prop. No offence Turbo, I don't agree with your head choice and I don't care what the numbers say. I do know what all the different head designs look like both on the flow bench and the dyno. Remember Dyno horse power numbers don't always translate to MPH numbers. We have all seen it before. " I have 50 more horse power and the boat is slower", Jim for YOUR usage and most any 18 foot Donzi owners 5500 is as fast as you should go on a 351 in that boat. I very rarely need to push past the 5000 rpm limit with one exception. That is if I find myself along side a copy cat Python Viper, then all the rules change. My Corsican is is nick named "Mongoose". Jim I am going to the Miami show, I can talk at great lengths on this subject. After I have worked with these motors since the early 60's. BTW I still have an origional set of hypo 271/306 heads. One last note if salt water is in the future, stay away from aluminum heads unless a closed cooling system is used. This post is from real live experience and not from a book some guy wrote

[mattyboy]

Big Griz,
great info ,
are there any way to tell the difference between the 3 visually??

[mphatc]

Big Griz,

I have to agree with you on all your points. Question, Your Corsican is a V-Drive, correct? Might that be why you're limited in speed, even with more HP?

My H&M experience is with a 302 . . . and from what I could tell when I disassembled my original engine last year other than the cam and the marine headgaskets there was nothing internal that was different from all the other SBFs I've rebuilt.

Jim G, I believe your doing all this work on an 18 with the original Volvo drive, and use of the boat is for pleasure . . so you should be looking for a strong flat torque curve and max power just short of max revs, while keeping your rpms not much more than 4900 - 5100 RPM.
There's no need to spin your engine higher. Your limited by the strength of the drive, and internal engine components will need to be seriously beefed up.

Keep it simple and reliable . . . I built my 302 with hypereutectic pistons and kept the compression ratio at the original 9.5 : 1 as I want the engine to be happy with 89 octane fuel, which is what is most common for marine gas.
NO Need for forged or alusil pistons!!! If you need pistons go with hypereutectic or OE Cast, as they can run closer cylinderwall to piston clearances, essential for a marine engine running cooling water from the lake or ocean.

In my rebuild I had to go with a new 302 block as the original 302 was cracked :frown: . . that opened up a huge can of worms!

The later blocks are all a different style, and use roller cams . . so I was unable to utilize my H&M cam. I acquired a cam from Bullet, custom ground. I used the GT40P heads, no porting or polishing as they can flow more than this engine will pump. Iit is all topped off with an Edelbrock Air Gap manifold and Holley 650.

Good Luck!
Mario L.

[Moody Blu']

i agree with everything mario said except for the part of the drive limiting the amount of power it can handle. the 250 drive can handle around 600hp without a sweat. better then any bravo.

[Rootsy]

better then any bravo.


Not quite sure of that one chief... plus... a bravo has trim and you can find parts pretty easily should you happen to actually break it with a small block :biggrin:

[Moody Blu']

Not quite sure of that one chief... plus... a bravo has trim and you can find parts pretty easily should you happen to actually break it with a small block :biggrin:
ok a stock bravo, captain

[JimG]

Well, I got the heads pulled. Found the reason for the failure: on the port head, the forwardmost head bolt had it's head sheared off. Apparently that allowed water to seep from the water jacket and corroded the head gasket. Confirmed no water in cylinders, just vented to outside. Lucky me! Everything else looks great! The heads are 1970 D00E-C's. Even the old Edelbrock logs look good.

I'll be ordering ARP fasteners today, head bolts/header studs/intake manifold bolts.

JimG

[Rootsy]

Well, I got the heads pulled. Found the reason for the failure: on the port head, the forwardmost head bolt had it's head sheared off. Apparently that allowed water to seep from the water jacket and corroded the head gasket. Confirmed no water in cylinders, just vented to outside. Lucky me! Everything else looks great! The heads are 1970 D00E-C's. Even the old Edelbrock logs look good.

I'll be ordering ARP fasteners today, head bolts/header studs/intake manifold bolts.

JimG

this might be overkill for the cylinder pressures you are generating and a bit more hefty on the wallet but consider using arp head bolt studs and don't forget a few packets of arp bolt lube. makes a world of difference when it comes to achieving consistant and accurate clamping force. well worth the extra 40 bucks or so imho

JR

[Moody Blu']

this might be overkill for the cylinder pressures you are generating and a bit more hefty on the wallet but consider using arp head bolt studs and don't forget a few packets of arp bolt lube. makes a world of difference when it comes to achieving consistant and accurate clamping force. well worth the extra 40 bucks or so imho

JR

a stock bravo I E no imco drive or beefed up aftermarket parts

[Rootsy]

a stock bravo I E no imco drive or beefed up aftermarket parts

last i knew an XR was a stock bravo.. as was an XZ... don't think i'd quiver too much with either one behind serious ponies... guess the sportmaster would be a stock lower too... :idea:

JR - stirring the pot some more :yes:

[ChromeGorilla]

damn...i didnt know there were so many bravo models...

Bravo I, Bravo II and Bravo III

Bravo 1X, Bravo 2X and Bravo 3X

Bravo 1XR, Bravo 1XR SMS and Bravo 3XR


not to mentiob the diesel bravo's....

[JimG]

Thanks for all your input, guys! I learned a ton on this thread!


Jim for YOUR usage and most any 18 foot Donzi owners 5500 is as fast as you should go on a 351 in that boat.

I won't even see 5500 in this boat. I know this is hard to believe, but I'm not looking for more speed. This boat is all original, with the old cable steering. 53mph is a white-knuckle ride! (My other boat goes 83mph, and has hydraulic steering/k-planes, etc. I'll save the speed for that boat...) With the Ultra prop, my Donzi is very easy to drive, gets on plane in an instant and handles great with none of the nasty habits it showed with an aluminum prop.

I'm going to work the heads, replace all the bolts and button her back up. I am considering an aluminum intake, maybe an Edelbrock Performer.

My top rpm is going to be 5000. At that rpm I'm seeing 53mph (gps) with my Ultra.

Thanks guys!!

Jim

[Moody Blu']

OK OK base model bravo l :rolleyes:

[Rootsy]

OK OK base model bravo l :rolleyes:

if i badger you for a few more days we might get you to a merc #1 drive :biggrin:

PS... matty how many ponies did it take to grenade your volvo? :wrench:

JR - soooo just HOW many ponies can an SS handle :smash:

[MOP]

I think you should go Merc Broque then you can offl the Volvo power power trim setup, someone will jump on it with only 216 fresh water hours that will defray some of the swap.

Phil

[mattyboy]

PS... matty how many ponies did it take to grenade your volvo? :wrench:
:smash:


about 310hp and 34 years ;) :)

I have a great video of it when it went too, the mech said at one time he think it hit something weakening the upper teeth, Now I use a 50/50 mix of 90weight and crest with flouride ;P
for healthy teeth and gums

[Rootsy]

the mech said at one time he think it hit something weakening the upper teeth


WOW me too!!! :jestera:

JR - my own mechanic :smash:

[turbo2256]

of 351 engines.!) Then the nect was a Cleavland engiiine that had big ports and 2.19 intake valves with a special intake manifold with giant ports. They only made about 250 of intakes and were also used on the pantera's. Then the most common Clevland used on Donzis was the big port head with open chambers(lo compression) and beleave it or not small valves of the 2.02 intake and 1.6?? exhaust valves. I have each of these combinations and have tested all of them with no less then 8 different cams combinations. One thing that I have found is that within 20->25 horse power my 18 Corsican's top speed doesn't change but 1 MPH. I now run the stock type 351M, heads which never put into a H&M boat engine, with a Babe Erson Max 108 cam. the only set of CMI hedders ever built for this engine and sounds better than my blown Criterion.
Jim What I would do,is put it back together with the same configuration, find a good set of exhaust and spend the extra money the prop. No offence Turbo, I don't agree with your head choice and I don't care what the numbers say. I do know what all the different head designs look like both on the flow bench and the dyno. Remember Dyno horse power numbers don't always translate to MPH numbers. We have all seen it before. " I have 50 more horse power and the boat is slower", Jim for YOUR usage and most any 18 foot Donzi owners 5500 is as fast as you should go on a 351 in that boat.
No offence taken Griz. But I dont agree with your head choice or H&M s either for a 351. One I would never think about using 4V heads on a marine engine even with smaller valves the 4v heads should not be used unless you going to run in excess of 7500 RPM or a blower the port volume is just too big at 244cc thats the way I build them except for concours engines.
The 2V heads are still a bit large for marine use the air flow numbers look good but the port volume is better suited for higher RPM use such as a hobby stock car or drag stuff. I have done many of the 2V swaps on C motors and W s. So you made a better choice using the 2V heads. If they were ported though some torq could have been lost.
The port volume on the 302/289/351Ws are much smaller better suited to low RPM use and great low end torq. E7s are around 130cc we open them up 3 to 5 cc's and get a bit better than stock 2V heads. We pick up air flow from .1 up not just on max lift. 50 HP increase with a loss in speed is typical of an over cammed engine or other miss matches in the engine combo that often increase HP on top with masive losses in power at lower RPM. You want to talk old engines I first started on a "Y" block ford, next a flat head, Holman and Moody they used to work in the building I am in. "8 cams" If I know the air flow and the RPM range required just one pick is needed. Cams almost mean nothing to me now cylinder head air flow and port volume do. Age card I rebuilt my first motor in 1958. as far as your boat only going 1 MPH faster with 25 more HP there is a designed hull speed and any attempt to go past it requires massive HP increases to get more. Grizz just trying to get you to open up yor mind . You can lead a horse to water but you cant make them drink.

[Moody Blu']

if i badger you for a few more days we might get you to a merc #1 drive :biggrin:

PS... matty how many ponies did it take to grenade your volvo? :wrench:

JR - soooo just HOW many ponies can an SS handle :smash:
all i said was a 250 can handle up to 600 hp (pushin it) a bravo1 stock would break somehting if it had no mods
a volvo 250 would be fine STOCK. mario did say the drive would limit the amount of HP .but thats no where near LIMITING jim on his mods to his motor. :confused:

[JimG]

Ok, not to throw fuel on this fire, but my stock Bravo has done just fine behind my 600hp 509 in my Thoroughbred. It's all in how you drive it, I guess... (loudly knocking on wood!) :eek:

Back to the Donzi... I'm taking my heads to Jim's Machine in League City on Friday. Thanks, Harbormaster for the tip!
Not going to do any porting, but I appreciate the information, Turbo! Just clean 'em up, possibly new valves, hardened exhaust seats.

What valves do you guys like in a stock head?


Anyone got a spare Edelbrock Performer laying around?

Jim

[Moody Blu']

Ok, not to throw fuel on this fire, but my stock Bravo has done just fine behind my 600hp 509 in my Thoroughbred. It's all in how you drive it, I guess... (loudly knocking on wood!) :eek:

Back to the Donzi... I'm taking my heads to Jim's Machine in League City on Friday. Thanks, Harbormaster for the tip!
Not going to do any porting, but I appreciate the information, Turbo! Just clean 'em up, possibly new valves, hardened exhaust seats.

What valves do you guys like in a stock head?


Anyone got a spare Edelbrock Performer laying around?

Jim

edelbrock performer rpm air gap manifolds run new for 231.95

polished is 389.95

or you could get a performer rpm and grind the plenum down about a inch and youll have a air gap ;)

performer rpms run 191.88 for a 351w

your choice.

I dont know if they have the permastar finish for the 351w but it looks pretty nice, a pretty good alternative to a polished maniold that will dull after time.

[mphatc]

Has anyone ever done this?
Take a new aluminum manifold and have it Jet Hot coated . . stops corrosion.
My local high temp coating says it works! They do a every set of exhaust manifolds on all the engines we build, but I have yet to try it on aluminum.

I had mine powder coated in white, but would have loved to do the one water passage in somethingto protect it against corrosion.

http://www.sivalves.com/home.html
greart source for SS valves, use these when ever possible on a marine application

Mario L.

[Rootsy]

Mario,

i've been looking into jet hotcoat and some other HPC coatings for intakes and even ports in cylinder heads for thermal and protective barriers.. i just have not gotten around to doing it for the last couple of years though... I have been using them on some applications at work though with decent results for the job at hand.

Blue,

IMO... for what JimG has done to that motor an RPM or RPM Air Gap is entirely too much intake manifold. btw, to the best of my knowledge the rpm and airgap have the same runners and plenum.. the air gap has a divorced plenum, therfore the word AIR GAP. Jim's setup would be MUCH better suited to a plain old edelbrock performer, or even the EPS if you can get it for the windsor. Port matched if he wants to take the time to do it won't hurt either.

JR

[Moody Blu']

Blue,

btw, to the best of my knowledge the rpm and airgap have the same runners and plenum.. the air gap has a divorced plenum, therfore the word AIR GAP. .

JR
from what i was told by a sumit racing tech. the only difference between the performer rpm and air gap is the plenum is cut about a inch down to create more turbulence. maybe thats not it?

[turbo2256]

My Seebold with a stock 330 7.4 carb motor only changes were an RPM Edelbrock and an 830 Holley. I then swapped heads for pocket ported Edelbrock oval port cylinder heads. Stock cam was retained. My first trial was with the RPM and the 830. It had better midrange with the Edelbrock heads. I then swapped the carb for a 750 out of the box. The boat ran the same with either carb. There was bow rise a bit quicker to plane after that it pulled much better to max RPM.
Next I swapped out the RPM manifold to a Torker II. Tried both carbs boat ran the same wihrt either carb one again. There was a differance in performance over the RPM manifold with the Torker there was no bow rise the boat came up out of the water with out it changing the angle that it sat in at rest and acceleration to max RPM improved over the RPM.
The air gap manifolds had just become avaliable and I slapped one of them on. It ran identical to the standard RPM manifold. Hope this is of some help. My thoughts if you have an RPM manifold switching to an Air Gap wount make a differance you can feel money would be better spent some were else. The Torker in my case went back on.

This is not out of a book just real world testing...lol

[turbo2256]

have also noticed during air flow testing of dual plane intakes the upper runners usually flow less than the lower runneres. Probably has something to do with the entrance angle to the port. Bottom line I dont like dual plane manifolds much. I would rather have a small single plane. Holley used to make some that ran the same RPM range as the dual planes. You might also be supprised how well the Torker II can perform on a mild engine.

[gcarter]

I had mine powder coated in white, but would have loved to do the one water passage in somethingto protect it against corrosion.

Mario L.
Mario, aren't you running closed cooling?

[JimG]

I just got off the phone with Holman Moody's cam grinder. He says my cam is :


280 duration
.470 lift
114 lobe sep

Turbo, what do you think? A candidate for a Torker? That's what the grinder suggested.

[turbo2256]

[QUOTE=JimG]I just got off the phone with Holman Moody's cam grinder. He says my cam is :


280 duration
.470 lift
114 lobe sep

Turbo, what do you think? A candidate for a Torker? That's what the grinder suggested.[/QUOTE

The Torker sounds good to me too. Just woundering what other mods are you doing to the engine? If you are not porting the heads just put the manifold on as it comes out of the box if you find a used one make shure it hasnt been modified.

[JimG]

No other mods at this time. $$ Tax time... :bawling:

Depends on what the machine shop finds on the heads, too...

Carb is 600 Edelbrock, exhaust is Edelbrock logs and HM snails.

[MOP]

Broque the Air Gaps plenum chamber is elevated with air flowing under it, helps to keep carb and runners cooler.

[JimG]

I think I'll try the Torker.

The heads are at the machine shop, so I'll know the verdict soon on those. If the valves are shot, I'm going Ferrea. I replaced all my fasteners with stainless, and pulled everything I could and polished or painted it. Should look good when it gets back together!

Jim

[JimG]

I checked the Crane site, and the H-272-2 cam that Forrest is running is very similar to the HM grind. (I don't have a complete cam card on the HM cam, just adv duration and lift on intake.)

H-272-2 (http://www.cranecams.com/?show=browseParts&action=partSpec&partNumber=443941&lvl=2&prt=5)

[BUIZILLA]

JG, great choice on cam. I like that 12* duration split with the log manifolds and unported heads.. If it was mine, i'd increase the static seat pressure to about 105#-110# @ 1.700 spring height, easy to do anyways right now if your going to get new springs, and you should be... Ferrea product is a good choice on valves. Torker is great idea, but your existing Edelbrock carb may like a Performer dual plane manifold better...(just my opinion) Above all else, and I can't stress this enough, make sure you try and degree in that camshaft, as some of these Ford specific timing sets are wacko out of the box... don't surface the heads tooo much or your going to run into a tight lifter plunger scenario.. screw it together carefully, and I think you'll be very, very happy with the results.
Good luck..
JH

[JimG]

I found a great intake manifold comparison for 302 Fords. Check out the Offy and the Weiand. Too bad they don't make those for a 351W....

Intake Test (http://www.jason.fletcher.net/tech/intakes/intakes.htm)

[turbo2256]

Thought those manifold flow #s were off a bit till I noticed they are taken at 25" not 28".

[JimG]

Interesting info on that manifold site, sure makes a good case for a single plane manifold in my boat.

Tony, what Edelbrock manifold are you running?

[Tony]

9/10 of this thread is WAY too technical for me, but two years ago I had my 302 rebuilt. After lots of great advice from this board, and lots of research, here's what I have:

Crane H-260-2 cam, 204/216 duration, 107/117 lift
World Products (Jack Roush 200) cast iron heads, 2.02" x 1.6" 11/32, 64cc chamber
TRW forged flat-top pistons
Eagle rods (SIR)
Hydraulic lifters
Moly top rings
Cleavite bearings
Ferrea Inconel marine valves
Z-28 springs, 100 lbs on seat
Comp retainers, keepers 10 degrees
Melling oil pump
Edelbrock Intake Manifold
Milodon oil pan
MSD Ignition
Holley #1611 carburater

They say 300 hp @ 5400 rpms, but I rarely wind it up that high, out of respect for my 38 year old Volvo AQ200. I know there is a ton of torque back there, if I knew what I was doing I would love to try a Volvo DP for some kickass holeshot. Maybe one of these years the 200 will kick the bucket, or maybe the damn thing will outlive me!

[turbo2256]

The dyno part of the test looks good to me except I am not shure which heads they used on the dyno motor. I just assume they were stockers.

The air flow bench part I am not so shure about. I do have some flow results on the Performer, Victor Jr, and a dual quad Blue Thunder intakes for a 302 but were tested with a valve at .5 lift. The part of the test were they used an aluminum head with the valve upside down is a bit bogus to me and my experences with an air flow bench.

[JimG]

The air flow bench part I am not so shure about.

The dyno runs were made on a 85 model crate motor, dunno what heads were available back then.

But I was amazed at how much torque and HP was gained by the single plane manifolds over the stock and dual plane designs. And still strong through the bottom. Since I run mainly between 3500-5000rpm, this seems ideal.

[turbo2256]

The dyno runs were made on a 85 model crate motor, dunno what heads were available back then.

But I was amazed at how much torque and HP was gained by the single plane manifolds over the stock and dual plane designs. And still strong through the bottom. Since I run mainly between 3500-5000rpm, this seems ideal.

Issues with dual planes
they are very difficult to port

the upper plenum has a different port entry angle than the lower

you have 4 short trunners and 4 long runners

the two short runners on the lower flow different than the short runners on the uppers

the long runners have the same problem

Even if you get the runners to flow the same on a bench they will not produce the same results because of the length differances

Basicly you end up with different HP in each cylinder and each cylinder having a different RPM peak.

The single planes can provide a more even cylinder filling than the dual planes.

Probably a dual carb setup would be the best with the carbs perty much centerd over the ports. With the advent of the distributorless ignition systems port to carb centering can be greatly inhanced. I have seen this done on a SBC a guy cut the runners out of the manifold and made his own upper. With some small carbs it runs great.

[JimG]

Got the heads back from Jim's Machine Shop. They look great!

I switched gears on the intake manifold after lots of research. Went with a Weiand Stealth. TONS of recommendations for that one!

I'll keep everyone posted on the results!

Jim

[JimG]

I got it all put back together and the dang manifold it too TALL!!! Now I'm looking for a low profile flame arrestor... :splat:

[turbo2256]

I got it all put back together and the dang manifold it too TALL!!! Now I'm looking for a low profile flame arrestor... :splat:
Thats one reason the Torker works I believe its the lowest profile for the flow. Anyway be careful those small flame aresters dont flow squat. The Wiend looks half way between a torker style and a vivtor jr.

[JimG]

I took it out on Saturday, ran like a champ! Had to fix a leak or two, but now everything is A-OK! I'll get it out next weekend for some real numbers. :D

[turbo2256]

I took it out on Saturday, ran like a champ! Had to fix a leak or two, but now everything is A-OK! I'll get it out next weekend for some real numbers. :D

Did you end up porting the heads? Congrats on it running.

[JimG]

No, just a valve job, seats and guides.

[JimG]

UPDATE:

Ran the Donzi yesterday! Ran 53.5mph, up from 52.5 previously. Rpm went from 5000 to 5100. Holeshot and midrange is very good, idles like a champ at 500rpm. I'm going to kick the drive out to the third hole and see if I can get any more...

Thanks to all who replied to this thread! I couldn't have done it without you! I'll post some updated engine room pics later...

JimG

[mattyboy]

UPDATE:

Ran the Donzi yesterday!


JimG

BITE ME !!!!!! ;) :tongue: :)


glad it worked out still spinning the ultra????

[JimG]

Yeah, Matty, still running the Ultra... :biggrin.:

Update: Ran again today, third hole. Ran 54.7!! Wow! That's movin' for that old dog! I'm REAL impressed with that Stealth!

[turbo2256]

What pitch prop are you running? What is the weight of your boat? What is your out drive's gearing?

[mattyboy]

did the rpm's come up any with the drive all the way up??
how was it at 55 did it get sqiurelly??

[JimG]

My Prop is an Ultra 22 with an inch of pitch added, so a 23" pitch. Drive is Volvo B 250, 1.61 ratio. Never weighed it, but contemporary reports put the weight at 2250lbs.

Matty, it was not squirrely at all. But, the torque steer came back with the drive in the third hole. Not bad, (unlike my uncupped alum props, which are downright SCARY), but it pulled to starboard and was stiff to port. I decided to move it back to the middle hole, because my wife is the primary driver of this boat and it's easier to drive that way.

The rpms were the same at 5100rpm, on either setting.

JimG

[turbo2256]

Do you know the dia of the prop

[JimG]

Ultras are 14"...

[turbo2256]

This is why I ask:
A 1.61 ratio with a 23" prop @ 5100 RPM in theory should reach 69 MPH.
A 1.61 ratio with a 23" prop @ 5100 RPM only reaching 54.7 would have a slip factor of 21 % (way to high of a slip #).

21 percent seems quite high 10 to 13 would be more average I would think. Using the 13 percent figure you should reach 60 MPH.

Now if use the 1.61 ratio with a 23" prop @ 4300 RPM in theory top speed should be 58 your 54.7 MPH would show a slip # of 6 % (this seems more realistic).


Another twist is a 20" prop @ 5100 RPM in theory would reach 60 MPH your 54.7 would indicate a slip # of 9% (quite realistic)

Have to ask is your tac right ?
Is your prop really 23 ?

[JimG]

Yes, my prop really is a 23". And I checked my tach against a mechanic's tach/dwell meter. It's dead on.

I don't know why, but my Thoroughbred runs a high slip number, too. Around 20%. No one's ever been able to answer it. I've tried everything, 5 blades/labbing/Hydros, you name it... I had to eventually just be happy with what I get. It's pretty close to what other T-Bred/Velocitys run.

I have an old Powerboat Magazine test of a 1970 18 2+3 w/ HM302, (I think they were using the old calibrated Nordskog Speed-O-Meter in those days, not as good as GPS/Radar but pretty accurate in it's day...), and they saw 51mph@5000 rpm with 23" pitch. That's around 25% slip.

Have a look at the post in the "True Lies" section. Run the numbers on the boats running Volvo drives. Most have slip numbers like mine. The alphas seem to be better.

Jim

[JimG]

Now if use the 1.61 ratio with a 23" prop @ 4300 RPM in theory top speed should be 58 your 54.7 MPH would show a slip # of 6 % (this seems more realistic).

BTW: I don't know that I've ever seen a single engine boat with a slip number that low...

[turbo2256]

BTW: I don't know that I've ever seen a single engine boat with a slip number that low...

My 236 Seebold figured out to 1%. My Sunsation has been down in the 5 to 3 % range. The Sunsation needs some final tweeking of the prop but I expect it to stay around 5%.

[turbo2256]

By the way slip #s are usally higher for twins.

[turbo2256]

My Apache looks to be around 3% but havent used the boat enough to be as positive as the other two.

[JimG]

WOW! Those are fantastic numbers! BAM's Prop slip site says:

"Slip is never a negative number, and will range from 5% on a light cat to 25% on a heavy workboat. Most hi performance applications will be between 7 and 12 percent."

What kind of props are you running? Who's prop slip calculator are you using?


Keith's new Superboat (Bravo 1 26") gets about 12%, Bill's 42 Sonic (26" P5X's) is down to about 11%. I'd be tickled to get anywhere near that.

[turbo2256]

Using Bam's just like you. Oh I could be off a bit but in the Seebold I checked tyhe tach accuracy. Need a check on the Sunsations tac but its not of much if any. The Apache I am unshure but should be close too. The Seebold was an off the shelf Hydromotive. The Sunsation is going to need some custom work. Throttle up has already done some work on one prop for it. Basicly blueprinted a hydromotive that was dammaged and will be reworked untill it shows loss of performance. Then I will back up a step and rework a new prop to the best results obtained from the used one.

[JimG]

On my Donzi, I'm pretty happy with where it is.

But I'm going to work on the T-Bred a bit. I haven't given Julie a shot yet, but I'm going to call her and see if she has any ideas. I'm running a Halls Velocity Stage 1 labbed Bravo 30" right now, and the slip numbers are still too high. I have a couple of Hydro Q4's that I might have reworked, too.

[turbo2256]

I have a friend that raced a 26 Velosity (now the 28) the Hydromotive prop ended up working out the best for him. His boat ran in the mid 90s. The bottoms of the Velosity and the Seebold are different. They handle quite similar the Seebold a bit more forgiving in turns. I think there bottoms are fairly even as far as drag goes.

[JimG]

My hydro 27" did better on top end (83mph), but holeshot and midrage (drivability) is MUCH better with the Bravo (79mph). Interestingly, the guy who works all of Velocity's props (Hall), runs a labbed Bravo for everyday use, and a Hydro for bragging rights just like I do! :biggrin:

[turbo2256]

My hydro 27" did better on top end (83mph), but holeshot and midrage (drivability) is MUCH better with the Bravo (79mph). Interestingly, the guy who works all of Velocity's props (Hall), runs a labbed Bravo for everyday use, and a Hydro for bragging rights just like I do! :biggrin:

I woud like to do some figuring on your engine setup in the Velosity. Just what cam, head flow, ect PM me if you would rather.

[JimG]

I woud like to do some figuring on your engine setup in the Velosity. Just what cam, head flow, ect PM me if you would rather.

It's 509", Merlin VR's, Brodix intake, blueprinted Holley 850, Ultradyne 296/306 cam, 112 degree, CMI e-tops.

[turbo2256]

Any port work done to those heads?

[JimG]

No work to the heads.

[JimG]

Update on the 351W:

I now have put around 10 hours since the head work/intake change. Engine's running like a champ! Janet and I dropped the Donzi in at the end of the Texas City Dike, and ran to CaptWK's place on Offatt's Bayou on Sunday. That was the first time I ran the boat with a full load. With all four of us, it popped right up on plane, no problem-a! Though it's always been strong on holeshot, the new manifold (Weiand Stealth) REALLY woke it up! Anyone considering a new manifold for a Ford ought to look at this one. Just beware, it's taller than stock...

JimG