PDA

View Full Version : Waking up a 351 with cam and heads



champ
01-29-2018, 09:13 AM
I have had my 17' Champ for about 8 years now and am thinking it is time to increase my horsepower some. This is due to needing to service my intermediate bearings which will be having me pull the motor.
I am currently running the 1:9 six cylinder gears in my volvo 280 outdrive, turning a 15x23 solas titan prop. I tried last year to change to a 270 outdrive with 1:61's and got everything hooked up only to find that the pivots were seized on the newer outdrive so I switched it back just so I could run it another season.
This year may be different. Mattyboy mentioned at one time by switching gears that I would not be able to turn the prop I am currently running without adding some more power to the motor.
Here is my question and without spending big money and I want to change the cam and add a newer set of heads to my 351 to wake it up. I am thinking of getting a set of gt40p heads or possibly some Winsdor jr.'s if it is in my budget. What cams and specs may be be a good choice for this motor and would you go roller.
Any thoughts?

Just Say N20
01-29-2018, 09:47 AM
If you want to run the Solas 23 with a 1:61 ratio out drive you will need about 400 hp and at least as much torque.

I had 440 hp and 495 ft lbs of torque turning the Solas 23 on a 1:61 Volvo 290. Could spin it to 5300 at 65, on a Donzi 16.

yeller
01-29-2018, 12:01 PM
Sorry, can't help you in regards to your main question, but when it comes to cams always go roller if you can. It's just a better, more reliable setup.

mattyboy
01-29-2018, 01:24 PM
again with the ford exhaust is going to be an issue going to a hotter cam may lead to a Hi Po exhaust. $$$$$


here are two benchmark/guidelines I used when redoing my ford note the 302 at 310 hp doesn't need a hi po exhaust the 351 at 350 does. just a reference from the shop that re-did my 302 . I have the cam specs on the 69 Holman Moody 351 which was rated at 290 ish hp that used standard glemwood log exhausts

302

Ford 302 CI Small Block Marine 310HP 360FT/LBS TQ
Block
Bored and honed with torque plate
1pc seal design non roller
Premium core max .040 bore. No repairs. No sleeves

Cylinder Heads
World 180 CC cast heads 1.94/1.60 58cc
New Head Bolts
3 angle competition valve job

Valve Train
Comp cam 218/218 456/456 110
High Intensity lifters
Cloyes True Double Roller timing chain
Scorpion Aluminum Roller Rockers 1.6 ratio
Screw in studs and Hardened guide plates
Manley .080 wall pushrods
7 deg hardened locks and retainers
1.94 int 1.60 exh Stainless valves
Performance springs

Rotating Assembly
Speed Pro Coated Hypereutectic pistons 9.7:1 CR
OE rods w ARP rod bolts
OE 2MAE crank 10/10
Balanced rotating assembly within 1 Gram
Speed Pro File Fit Moly Rings
50oz Balance

Intake and Tinware
Professional Products Dual plane Manifold
Professional Products Damper 50oz
New OEM Front sump Pan
Tall Chrome Valve Covers
New Aluminum universal timing cover
New OE 50oz Flywheel

351

Ford 351 CI Windsor Marine 350HP 400FT/LBS TQ
Block
Bored and honed with torque plate
1pc seal design non roller
Premium core max .040 bore. No repairs. No sleeves

Cylinder Heads
World 200 CC cast heads 2.02/1.60 60cc
ARP Head Bolts
3 angle competition valve job

Valve Train
Comp cam 226/234 512/531 111 requires performance exhaust
High Intensity lifters
Cloyes True Double Roller timing chain
Scorpion Aluminum Roller Rockers 1.6 ratio
Screw in studs and Hardened guide plates
Manley .080 wall pushrods
7 deg hardened locks and retainers
2.02 int 1.60 exh Stainless valves
Performance springs

Rotating Assembly
Speed Pro Coated Hypereutectic pistons 9.0:1 CR
OE rods w ARP rod bolts
OE crank 10/10
Balanced rotating assembly within 1 Gram
Speed Pro File Fit Moly Rings
28oz Balance

Intake and Tinware
Professional Products Dual plane Manifold
Professional Products Damper 28oz
New OEM Front sump Pan
Tall Chrome Valve Covers
New Aluminum universal timing cover
New OE Flywheel

mattyboy
01-29-2018, 01:37 PM
may be more economical to drop to a 21

champ
01-29-2018, 02:51 PM
I am using the Glenwood high performance now, so flow should not be problem. Still have the old H/M's too, but my guess is the Glenwoods are better? Trying to get around 300 hp, maybe a little more. A little less prop is o.k. too, not trying to go 65. Still have an ultra 14x22, any thoughts on that?

Just Say N20
01-29-2018, 06:15 PM
300 hp with a 1:61 drive will spin an Ultra 22 nicely.

mattyboy
01-29-2018, 06:58 PM
+1 on what bill said
I ran a 22 ultra until I spun the hub then a 21 Solas
The end dump risers are ok would be better with center risers if they fit
I will look for the specs

mattyboy
01-30-2018, 06:26 PM
sorry can't find the 69-70 290 hp cam specs I have the newer detuned 240 and 255 hp specs that came along in the mid 1970s on the 351

JimG
01-31-2018, 10:41 AM
I got these specs from the original cam grinder at H&M... 290hp


280 ADV duration
.470 lift
114 degree lobe sep

Carl C
01-31-2018, 12:22 PM
I like the Windsor Jr. heads. They have a smaller combustion chamber than the Windsors so you won't lose compression and the exhaust ports are the same as the Windsor. Intake ports are a little smaller. The main drawback in a boat might be that they are heavy cast iron.

mattyboy
01-31-2018, 01:03 PM
The biggy is lobe separation and valve overlap what works to make hp in a car doesn’t work with a wet marine exhaust reversion is a killer

I never had any issue with my logs but I never went above the stock marine cam the logs are tough on the rear exhaust valves heat wise when you leave the stock world the longer runners of a center risers or headers are better

champ
02-03-2018, 12:29 PM
If you want to run the Solas 23 with a 1:61 ratio out drive you will need about 400 hp and at least as much torque.

I had 440 hp and 495 ft lbs of torque turning the Solas 23 on a 1:61 Volvo 290. Could spin it to 5300 at 65, on a Donzi 16.

So what kind of make/ size motor are you running?

Just Say N20
02-04-2018, 09:32 AM
So what kind of make/ size motor are you running?

1972 Chevy 400, 1972 ported/polisher double hump 202 angle plug heads, Edelbrock aluminum dual plane intake, Holley 750 double pumper, CMI header exhaust. Don’t remember the cam specs.

woobs
02-04-2018, 11:12 AM
Please post up the cam specs/performance when you get it sorted.

I too am building a 351W (with HM logs) and looking for at least 300+HP and as much torque as I can find.
I am considering building a stroker to boost the TQ and will be using Aluminum heads (Edelbrock Performer) to lower weight.
Not sure if I'll be dropping large on a FI system or staying tried, true and affordable 4bbl.

By far, the biggest concern is the cam specs.

mattyboy
02-05-2018, 07:56 AM
C9OZ-6250-A thats the cam for the 69 to 71 351w


here is a duplicate from howard have to cross reference what JimG posted

http://www.competitionproducts.com/Howards-Cams-Hydraulic-Flat-Tappet-Camshaft-Ford-Small-Block-351W-1969-1996/productinfo/227571-14/#.WnhibK6nG00

turbo2256
02-07-2018, 10:16 AM
I would want a cam with about a .500 lift thats about were most SBF heads peak flow
something like a B cam with a bit more exh duration to make up for wet exh but should be no reversion
A torqer II intake
good exh a must


best exh

V
V
V

turbo2256
02-07-2018, 10:25 AM
MIGHT use someting like the heads here with 170 cc ports and 1.9 valves

http://www.edelbrock.com/automotive/mc/cylinder-heads/ford/performer-rpm-sb.shtml

Also might consider GT40 heads ported

woobs
02-07-2018, 04:09 PM
MIGHT use someting like the heads here with 170 cc ports and 1.9 valves
http://www.edelbrock.com/automotive/mc/cylinder-heads/ford/performer-rpm-sb.shtml
Also might consider GT40 heads ported

I read a comparison article on aluminum heads for 5.0L (302) and the Edelbrock Performer was the best bang for the buck. Not the absolute best in terms of dyno performance but, not too far off. I was surprised how bad the stock GT40 heads were.

Back to the cam... there seems to be a lot of choices here:
http://www.lunatipower.com/Category.aspx?id=68

turbo2256
02-07-2018, 05:42 PM
i ported GT40s that out flow the smaller port edelbrocks and others say in the 165 170 180 cc port sizes.
The 351s need a bit larger ports than the 40s actually but ported well do some low end torq.
A hydraulic roller would be a good choice link bar lifters are a bit pricey.
Something around 218 216 @ .050 intake ... 224 ish @.050 exh .500 lift a bit more on exh. advertised duration 260 270 area
would most likely use a torqer II intake

My 302 powered car runs a ford B cam with ported DOOE heads flow about the same as ported gt40s pulls 420 FWHP. This engine would do well in a boat although i realize many car engine builds wouldnt.
exh would need a bit more lift and duration on the

turbo2256
02-07-2018, 06:04 PM
bottom one on this page for flat tappet hyd
http://www.cranecams.com/212-219.pdf


top 2 here maybe 3rd one for hyd roller
http://www.cranecams.com/220-223.pdf

not necessary this brand but similar cams

woobs
02-08-2018, 08:13 AM
I'm sure your GT40 heads do flow well. But, my issues are;

1) Who would I get to do the porting locally and how can I trust them? 1b) Do they have experience with performance marine motors? (probably not ... in Toronto)
2) What does it cost for a quality porting job by a well known builder?
3) What is the cost difference from buying GT40 heads and porting them vs. purchasing an Edelbrock aluminum set ready to go?
4) How big is the difference in performance between the two heads given it generally takes about 10 HP to go 1 mph faster?

Given the Edelbrock product is a known commodity and the ported head will be different with each head, I think I'd go with what is proven and I can trust, to spend my money on.
The only way I'd do GT40 heads ported is if 1) I already owned a set of heads and... 2) I could do the work myself properly (I don't have that skill) or... 3) I had access to a proven engine tech with plenty of experience porting marine engines for my application and...4) There was a significant cost savings or, substantial performance increase with the ported heads....

But again, heads are not the big unknown. Cams are. What HP/TQ levels do those cams (posted above in links) support?

turbo2256
02-08-2018, 10:42 AM
i can understand all your concerns. have built engines for many different venues ported a lot of heads and flow tested many competitors. example a set of edelbrock roval port heads that i installed on my 1988 23' 6" Seebold 454 that had the peanut port heads.
They didnt flow their advertised numbers until i pocket ported them flow was 290 @ .500 lift.
with no changes to the 400 hour 330 hp short block just installed the heads and tried 3 different intakes.
a performer RPM, a Air Gap and a Torker II. the RPM and the Air Gap ran about the same as when it had peanut port heads and couldt fell any difference between them. the Torker II on the other hand the boat jumped up on plane and hit the rpm limiter 75 mph so quick my 10 year old son noticed the difference. It was like adding a 100 HP shot of NOS. reproping might have reached over 80MPH

So air flow is HP a HP factor more so than cam. What is most unknown is what intakes do to air flow when possible have flow tested intakes bolted to a head gives better info on whats going to transpire.
Cam is more about what RPM the HP/ TQ need to be for the application. Marine , jet boats, street, oval track, towing, strip, etc are all different. towing , off road, marine might be close to being similar.

Building a 302 would go for ported factory iron for best results except some really high RPM usage as the port volume vs engine size matches up well

Now building a 351 would recommend aftermarket heads. marine use 165 to 175 CC ports would also favor 1.9/ 1.6 valve sizes . So other things for marine build would be port locations best to remain in stock locations especially on the exh.
Most of the heads in the above mentioned CC air flow reaches best flow around .500 lift then starts to only increase 5 or 10 cfm if that much. Look for the heads with the best flow rates at the low lift points below .500.
got to go will talk intakes next

turbo2256
02-10-2018, 09:16 AM
a couple thoughts have come to mind. one is the edelbrock heads have a 1 3/8 x 1 3/8 port i believe this is a bit larger than a stock ford head possibly larger than most SBF gaskets. Is there enought meat on your manifolds to match up.

the larger heads put the 351W within the same power potential range as a SBC with similar heads. Might look into cams used for marine use in the SBCs and find ford cams with similar grinds. Have read a few test were they built a 351W and a 350 as similar as possible were they produced only a 5 hp difference. have to wounder what cam was used in the 377 scorpion engine.

Found edelbrok offers marine use coated BBC heads as a while back was suggesting parts for a engine build for a marine shop here. Dont know if its the same mill spec coating used on the SBC Brodix heads though.