resurrected

I am re-powering my 1978 233 formula, currently it has twin 350's. I was going to rebuild to 383's , but have been given an opportunity to use LS6 GM crate motors. It sounds too cool to be true! But I am concerned about the torque curve and where to get exhaust, and cooling system. I'm very excited about the possibility if this engine pkg. Any opinions good or bad would be greatly appreciated.

JohnJan

Those would be very cool. I'm thinking that the R&D required to marinize them and make them work would not be worth the cool factor though. Exhaust alone would be a huge project, and once they're done, would they work well enought to not reduce the power and torque. Would the EFI mapping meet the requirements of marine use?

It'd be a HUGE project!

resurrected

Thanks for the comments! The exhaust is my major concern. If I have to I can get a buddy of mine to fab. it. He makes custom stainless exhaust for GT cars. I also have another friend who can tweak the ECU. But with friends, this type of stuff takes huge time and calls in big favors! Even if I spent a season tuning I think it could be worth the effort. I don't know what it would take to marinize the engine. Its all aluminum and I run in fresh water.

88Fount33

Closed Cooling system would allow the Aluminum to last. I perfer displacement. My choice would be 383's. I repowered an 1983, 18' Formula with 260 HP to 406CI small block with annodized aluminum heads. 62 mph to ~80 with the change. Way too fast for the hull. Detuned by converting from solid lifter cam with roller rockers to smallish hydraulic cam speed back down to 62 but with killer torque. Went from not wanting to plane with moderate load to pulling right up no matter how heavily loaded, and how heavy the skier (S). 10:1 compression with Brodix heads and dual plane intake and 750 CFM carb. Went from 23" 3 blade cleaver to 27" 4 blade hydromotive (drive killer). cruise RPM dropped from 3000 to 2100 rpm for identical speed. (Closed bow boat)

resurrected

I like the idea of a closed cooling system for the aluminum engines. What size of a heat exchanger would I need? I agree the 383 would make more torque than the LS6. But I think the weight savings might be be worth the 50 or so ftlbs I would be giving up. How much RPM can an Alpha take? The LS6 has good power up to 6000 RPM. That would be a shame to have to de-tune an engine!

outriggers

Check out the small blocks at worldcastings.com . It would be cool to put together a 454 sbc. Talk about a drive killer. Doug

CIG3

I like the LS6 idea. You will have to change the camshaft as part of your marinization. Does your ECU require an oxygen sensor? That may take a computer guy to eliminate.

The exhaust shouldn't be a problem. An adapter plate is all you would need 3/8" steel. I've uses big chief headers on standard big block stuff for years.

The closed cooling system is available right from CP Performance or out of the the back of the Yacht Trader.

ratman

kiss, keep it simple stupid, live by this mantra. i built a 383, it was a monster for torque. i used a new (no core needed) scat cast steel crank ready to drop in the 350 block for around 200.00 some reconditioned 5.7 oem x rods from smmit about 100.00 per set. trw forged flat tops, oem cast iron 882 large chamber heads and a doug herbert 550/550 lift 245/255 roller. it made ungodly torque from 2 grand to 7500 where the rev limiter kicked in. i used a single plane int. with 750 dbl pumper 4150. cheap power and it ran nice n cool. go for the 383's or 388's @.030

resurrected

Thanks! I understand the KISS rule quite well, but if there is a way I can be as different as possible I will, I haven't ruled out the 383's yet! I will deal with the obvious problems before I make a desicision. about the LS6-any recommendations for cams? I have a guy that can work miracles with the ECU. Are the Big Chief headers cooled? Where can I get the headers? Thanks alot I am excited about the LS6's , so I hope I can make it happen!

WETTE VETTE

Tom Stolarz @ WPM Racing has an LS6 based motor in a 23' WPM Cat and according to him it is pretty awesome! I think his makes close to 600 HP. I am sure he would be glad to offer some assistance and probably has necessary parts available for marinizing these.