18 with a 496?

[donzi182003]

I was up thinking last night. Wouldnt it be cool as all hell to have a 496 HO in an 18 classic. I heard from someone that its been done. Is that true? Is it even possible? All I know that if it is,,, thats my next boat. Let me know if you guys have heard of something like this.

Ed

[RedDog]

Other than the "new" factor it wouldn't be that different from one with a 454. There have been a few around with a 454 having similar power to the 496 HO :yes: ;)

[ChromeGorilla]

Sure it would be cool but wouldn't it be better to build a SBC to the same HP? Save weight and space. Just a thought.

[Carl C]

Seems like an awful lot of weight for an 18. If you want that kind of power I'd go with a bored, stroked and blown small block with alum. heads.:yes:

[donzi182003]

Three words... Big block sound

[Woodsy]

I think a 496 HO 18 Classic would be a mighty cool boat. It would probably push an 18C well into the high 70 MPH range. Of course getting it insured is something else entirely.

Woodsy

[Dregsz]

A 496 is just a 454 withan aditional 1/4 of srtroke.

There is no difference in extrernal dimensions of any big block chevy so a 496 takes up no more space or wt then a 598 ci motor or 632 ci motor

[RedDog]

A 496 is just a 454 withan aditional 1/4 of srtroke.
Does the 496 have a different cylinder firing order?


There is no difference in extrernal dimensions of any big block chevy so a 496 takes up no more space or wt then a 598 ci motor or 632 ci motor while the 496 takes no more space, the 454 is still a really tight fit.


did someone say cool sound...

[cigarette30]

A 496 is just a 454 withan aditional 1/4 of srtroke.

There is no difference in extrernal dimensions of any big block chevy so a 496 takes up no more space or wt then a 598 ci motor or 632 ci motor

I had a 1977 X-18 with a factory 370 (454 block), and a TRS drive. VERY TIGHT. Considering the 496 has the fresh water cooling manifold across the front, from what I remember, it would never fit. In addition, the height was so compromised, the hatch had scoops on the rear just to clear the exhaust manifolds. Speed, an honest 74-76, so it would appear a very healthy SB (OK I bit my tounge) would be better. On a side note, when you came off a plane, and forgot to put the trim tabs down, everyone got a nice bath, that much water would come over the transom. Cool, heck yeah, practical ...ummmmmm not.

[cigarette30]

I think a 496 HO 18 Classic would be a mighty cool boat. It would probably push an 18C well into the high 70 MPH range. Of course getting it insured is something else entirely.

Woodsy

On that note, at the time insurance was not available at all. Even tried Lloyds of London. Today it probably is. They had max HP per foot then, an 18' Hydrostream, with a 200 hp outboard, (an 80mph "surf board") was OK, but the much safer Donzi, no way.

[DonziEd]

I would think it would porpoise because of the weight at the transom. It would pop up like a dragster on take off. :yippie:

[txtaz]

Ed, I have been thinking about options for my 18c 350 MPI. A BBC would drop the transom too far in the water, a procharger is expensive and takes more room in the engine compartment and be obvious you have power (ie no sleeper here). I'm starting to look into tuning the engine like racers do. Balancing, porting, polishing to start with then tweak the ECM for higher RPM's. May need to change injectors, pistons and rods. In the end I want a stock looking SBC.
To be honest, a few weeks ago was the first time I was behind a 350 MAG with headers at speed and it sounded darn good. The BBC has a litlle lower rumble, but I'm happy with the sound mine make with the Stainlesss Marine exhaust.
I'll let you know what I come up with.
Wes

[Barry Phillips]

Big block 18's are not unheard of, I even think Donzi offered a 454 equipped 18 at one point, but I agree with everyone else the 496 is a lot of motor for a boat as light and tight as an 18. You certainly don't need that kind of torque. If you want a reliable turn key motor, I would suggest a stock 320 hp 6.2 Horizon MPI running through a Bravo 1 drive, no muss, no fuss, no bother plus good fuel economy. I have herd rumors that Mercury Marine is launching a more powerful small block, just a rumor, but I hear it from a certified Mecrusier Shop. So keep an eye Mercury Marine's web sight. I will ask about it on the weekend.

[donzi182003]

Im happy with the power on my 18 I just want my next boat to be STUPID fast. I never really ran this one that hard because we dont really have the smooth water that often and I am an outboard fan and fear I/O 's reliability.(paranoia of course not fact). When I buy my next boat it will be a 22 with a 496 HO (I wish I could buy IMSAC00's boat) or an 18C with BBC power. The 22 with the MAG HO is a boat that I at times have to pull the throttle off at WOT and my 18 usually doesnt lose it as bad. I just love that floating feeling at 73-75 M.P.H.!!!!!!

[joseph m. hahnl]

I was web surfin and found this hot rod sight. It stated some imformation which appeared to be inacurate. Maybe my thinking is wrong so feel free to correct me. they where talking about a small block 400 and how you couldn 't get them any more. and how a 383 was the only thing you could get. it went on to say a 400 was a 4.5 bore by 4.0 stroke and a 383 was 4.0x4.0
Now I thought a 383 was a 350 crank with the throws ground .090 off center.
which would be 4.0 X3.590
and a 400 was 4.0 bore with 3.75 stroke.

is that correct and if so is a 4.0 crank still made and will it fit in any SBC.

joe

[Cuda]

I remember at least one Sbc being a 406, and I'm pretty sure I've seen even bigger written about.

[RedDog]

I would think it would porpoise because of the weight at the transom. It would pop up like a dragster on take off. :yippie:

Porpoising was never a real problem in the former Genuine Trouble - former Genuine Risk (420 HP - BBC), nor was popping up on take off - planed off real fast. However the dragster analogy is correct - acceleration wise. Although I no longer have the boat (Blackie does now - named Nervous Energy) it was a fun combination. It did sit lower but that was no major issue - the extra torque made up for it. :cool:

[boldts]

I just love that floating feeling at 73-75 M.P.H.!!!!!!

Yep, nothing like running a 22 at wide open and feeling the bow just floating on a cushion of air. Makes ya feel like your driving a much bigger offshore race boat. Yes, I miss mine terribly! :embarasse

[joseph m. hahnl]

I was web surfin and found this hot rod sight. It stated some imformation which appeared to be inacurate. Maybe my thinking is wrong so feel free to correct me. they where talking about a small block 400 and how you couldn 't get them any more. and how a 383 was the only thing you could get. it went on to say a 400 was a 4.5 bore by 4.0 stroke and a 383 was 4.0x4.0
Now I thought a 383 was a 350 crank with the throws ground .090 off center.
which would be 4.0 X3.590
and a 400 was 4.0 bore with 3.75 stroke.

is that correct and if so is a 4.0 crank still made and will it fit in any SBC.

joe




Well I did some research and it turns out i was way off.
a 400 had 4.125 bore with a 3.75 stroke
wich would make a 383 a 4.0 bore with a 3.75 stroke

joe

[Lenny]

There were a couple of boats here in the past with 400's I believe. Maybe it was Paulo and GeneD. I don't remember.

[cigarette30]

[QUOTE=Barry Phillips]Big block 18's are not unheard of, I even think Donzi offered a 454 equipped 18 at one point, but I agree with everyone else the 496 is a lot of motor for a boat as light and tight as an 18. You certainly don't need that kind of torque.

They did, and it was Roy Farmer that told me, "a stock package with 70-75 mph top end," a dream come true. At that time, stock SB, would not make the mark. It was a great boat, and yes the torque was incredible, you could "hit it" at 3000 rpm's and have the boat leave the water if trimmed up. Great ride, just not real practical. Still wish I had it though ........... traded it for a home foundation believe it or not in 1989, then bought a new 18 Classic with a 350 Cobra with a 64 mph top end.

[GEOO]

I like the idea. 6.2 weight 993lbs, 496- 1199lbs, ( 200lbs , 3" longer, 3" wider, 2" taller.) Should fit?? I think a small block 425hp vs. BB. The BB would be faster. Makes more torque and moves cg back so would need less trim to air the boat out. :lookaroun

[ChromeGorilla]

Man even Merc's SBC's come in at just a tick under 1000lbs...... just imagine Ilmors MV-10 625.... weighs 800lbs w/ full CMI headers..... :yes: Do you really need a back seat in an 18........ :eek!:

[GEOO]

Chrome... Cool Idea. Ted was toying with that for a while...
Merc. lbs. is with the drive.

[RedDog]

I like the idea. 6.2 weight 993lbs, 496- 1199lbs, ( 200lbs , 3" longer, 3" wider, 2" taller.) Should fit?? I think a small block 425hp vs. BB. The BB would be faster. Makes more torque and moves cg back so would need less trim to air the boat out. :lookaroun

200 pounds - thats like me sitting in the back seat - or a tank full of gas. Torque = acceleration = fun. Acceleration fun > speed fun.

You do need a raised hatch - see pic

[Carl C]

You do need a raised hatch - see pic A scoop would look good. and be functional.:)

[blackhawk]

I like the idea. 6.2 weight 993lbs, 496- 1199lbs, ( 200lbs , 3" longer, 3" wider, 2" taller.) Should fit?? I think a small block 425hp vs. BB. The BB would be faster. Makes more torque and moves cg back so would need less trim to air the boat out. :lookaroun

Exactly! Now replace the stock exhaust manifolds and drop another 60-80lbs! Although I don't have a Donzi any longer, when I dropped the 5.7 GXi in my 19 footer I REALLY wanted to put in a 496 and I was talked out of it by several people. Looking back in hindsight I wish I would have done what I wanted and dropped the 496 in. No taller than the 5.7 I put in either. If I keep the boat I will have a 496 in it next year. :yes: I have already "tested" the boat for a BB! :D

[joseph m. hahnl]

A mild 383 stroker will push an 18 76 - 78...


All day long......

Poodle: do they grind the crank journals to fit the stock block? Or do you need to line bore the main bigger?
just curious what you actually need to put a stroker crank in a magnum 350.

Crank and Rods and bored to 4.030?
(stock 4.0 bore =377cid)
Some one told me the merc block has heavier and bigger water jackets. Is the marine block really diffrent then an auto block?

I found the formula if you all need or want for displacment
R2 x pie x stroke x cylinders

pie= Not apple or cherry;) but 22/7:yes: or round it to 3.14:idea:
R2= your bore / 2 x itself:rolleyes: :tongue: :lightning











joe

[Lenny]

Has anyone thought of using GM's C-5 C-6R 427? :D


LS7 engine

The all-new LS7 of the ’06 Z06 reintroduces the 427-cubic-inch engine to the Corvette lineup. Unlike the previous 427 engine, which was a big-block design, the new 7.0-liter LS7 is a small-block V-8 – the largest-displacement small-block ever produced by GM and a tribute to its 50 years as a performance icon.

With 500 horsepower and 475 lb.-ft. of torque, it also is the most powerful passenger car engine ever produced by Chevrolet and GM. The LS7 is easily identified under the hood by red engine covers with black lettering.

The LS7 shares the same basic Gen IV V-8 architecture as the Corvette’s 6.0-liter LS2, but the LS7 uses a different cylinder block casting with pressed-in steel cylinder liners to accommodate the engine’s wide, 104.8-mm-wide cylinder bores; the LS2 has 101.6-mm bores. And when compared to the LS2, the LS7 also has a different front cover, oil pan, exhaust manifolds and cylinder heads.

Maybe a bit "too" esoteric.

[JPR]

I think the corvette engine would be amazing, there is a rumor that GM will be selling this as a crate engine, so maybe not all that unrealistic.

[MOP]

No Rumor! :odie: :checkered

http://www.crateenginedepot.com/store/LS7-Crate-Engine-Small-Block-17802397-Coming-Fall-of-2005-P930C0.aspx

[joseph m. hahnl]

I personal feeling is: you can obviously make a small block push some seriuos horse power and torque. With out having to modify any part of the hull or placement of the motor. the only advantage to a big block to me is a stronger casting as everthing in it is beefier. it would also seem it is a lot less work to build a motor that fits than to build one that you need to modify the boat too.
It's one thing if the boat allready has one but to retro fit it would be way to much work for me and would take away from my limited boating season.
If i decide to modify my mag it would be the 3.75 crank .I believe it is stroke not bore size that creates lower Rpm and torque. I give you permission to correct me if you Know differently:wavey:

joe

[JPR]

Thanks for the link MOP, incredible engine - the spec's did not give a weight, though - any idea on that?

[Lenny]

Keep in mind (if a long block is ever available) you will need an intake manifold, EXHAUST manifolds which will be a stickler, marine electrics, and fresh water cooling if a salt bound boat, crossover, etc. There are a lot of "items" that would be needed to (manufactured or newly supplied) in order to make this happy in a boat tho. Makes it similar to the Ilmor option probably.

http://www.ilmor.com/550.html

Also, I don't think too many drives will like max HP at 6800 rpms. :eek: The Ilmor is more in band with a Bravo scenario.

[blackhawk]

I personal feeling is: you can obviously make a small block push some seriuos horse power and torque. With out having to modify any part of the hull or placement of the motor. the only advantage to a big block to me is a stronger casting as everthing in it is beefier. it would also seem it is a lot less work to build a motor that fits than to build one that you need to modify the boat too.
It's one thing if the boat allready has one but to retro fit it would be way to much work for me and would take away from my limited boating season.
If i decide to modify my mag it would be the 3.75 crank .I believe it is stroke not bore size that creates lower Rpm and torque. I give you permission to correct me if you Know differently:wavey:

joe

Well, there is another advantage to a BB. STOCK power! :D

[joseph m. hahnl]

No Rumor! :odie: :checkered

http://www.crateenginedepot.com/store/LS7-Crate-Engine-Small-Block-17802397-Coming-Fall-of-2005-P930C0.aspx



Very cool: Machined ports. $13,000 Oh my the price of addiction is startleling!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!:bawling:

[BLACKIE]

Here's a couple of photos of Nervous Energy's engine. It's a little tight but I can easly get to the plugs and drains. It does have touque most noticable when reducing throttle from a WOT run. As long as your ready for it its not a problem. I would not recommend an inexperienced driver going WOT in a BBC 18' without some serious seat time though. It will make for some exciting moments for the unintiated. Most of the other stuff you can trim out and it really rides nice at speed especially straight into a light chop (1 to 2 footers). I've not really noticed a lot of water coming over the transom when reducing speed. If you come off plane slowly its OK, if you chop the throttle the back seaters are going to get wet.

I'll tell you what, there is nothing like that BBC sound up over 4,000 RPM's.

Here's some pictures of Nervous Energy's engine.

[BLACKIE]

Nervous Energy's engine is a 454 outputing 420 HP. It was built by Second Effort. I think it was OMC's attempt at putting BBC's into 18' Classics. Don't know much about them though. Would like to hear from anyone on the board that has any info about these engines........ :yes: :yes:

[blackhawk]

Here's a couple of photos of Nervous Energy's engine. It's a little tight but I can easly get to the plugs and drains. It does have touque most noticable when reducing throttle from a WOT run. As long as your ready for it its not a problem. I would not recommend an inexperienced driver going WOT in a BBC 18' without some serious seat time though. It will make for some exciting moments for the unintiated. Most of the other stuff you can trim out and it really rides nice at speed especially straight into a light chop (1 to 2 footers). I've not really noticed a lot of water coming over the transom when reducing speed. If you come off plane slowly its OK, if you chop the throttle the back seaters are going to get wet.

I'll tell you what, there is nothing like that BBC sound up over 4,000 RPM's.

Here's some pictures of Nervous Energy's engine.

Very nice! What kind of speeds do you get it 1-2' chop?

[Lenny]

72-74 I believe, GPS, 78 on speedo, if I remember correctly, when I was looking at it at the end of 2000...

Correct me if I'm wrong Blackie. :D

[BLACKIE]

Your right on Lenny, I've not taken my GPS out with me yet, probably because I can't hold it while I'm driving and my passengers won't let go of the weine bars to hold it either. I don't get to drive it much on smooth water on lake St. Clair. It seems the wind is always blowing and there are many other boats running in all different directions. It makes for some interesting wave patterns sometimes. They come up fast when moving at 60 to 70 MPH and you will catch some serious air if your not paying attention. I haven't been thrown out yet but I've lost just about everything in the boat that isn't nailed down, towels, bumpers, ropes, coolers, etc. :biggrin.: :biggrin.: I've had to backtrack several miles sometimes to find the stuff floating in a long line. :cussball: I'm sure it's happened to some of the other guys with 18's.

[RedDog]

72-74 I believe, GPS, 78 on speedo, if I remember correctly, when I was looking at it at the end of 2000...

Correct me if I'm wrong Blackie. :D

The best I had in her was a little over 71. I think Rick claimed a little more by running less fuel and by removing the hatch to get better air flow to the carb. But then I'm certain Rick could get more out that 18 than anyone else. Shortly before Blackie bought her, Rick and I were out together. We swapped boats. I moved to his 22 with Donzi Deb and his "Boss." He moved to the 18 with my son. The water was really rough from all of the weekend boat traffic and I still couldn't keep up with him with me in the bigger 22. He can ride WOT in conditions I must back down in. My son certainly had some excited comments about the ride!

[Lenny]

It seems the wind is always blowing and there are many other boats running in all different directions. It makes for some interesting wave patterns sometimes. They come up fast when moving at 60 to 70 MPH and you will catch some serious air if your not paying attention. I haven't been thrown out yet but I've lost just about everything in the boat that isn't nailed down, towels, bumpers, ropes, coolers, etc. :biggrin.: :biggrin.: I've had to backtrack several miles sometimes to find the stuff floating in a long line. :cussball: I'm sure it's happened to some of the other guys with 18's.
I think you ARE THERE :yes:

Fun ??? ,... definately... happy to know you have "rung it out" ...

Happy boating :) be safe...

[N2DEEP]

BBC with cast manifolds in 1978 18....Tight!! I can"t fit in to do much, the marina has had to hold the "SMALLEST MECHANIC" upside down to do some work in the engine compartment.

[cigarette30]

BBC with cast manifolds in 1978 18....Tight!! I can"t fit in to do much, the marina has had to hold the "SMALLEST MECHANIC" upside down to do some work in the engine compartment.

That's It! can you imagine the Merc. or another 496 with fresh water cooling manifolds (did't the 496, due to some aluminum parts mandate FWC?)

Can't see it ever fitting. Still was cool, gotta love a big block