572 Engines what differant
 

I have 2 572 gm performance engines brand new in the crate was thinking about replacing my 502mpi's with them the 572s have forged steel cranks and full roller valve train forged aluminum pistons .632 lift 254-264 duration 9.6:1 compression & rated at 620hp was thinking about putting them in and add whipple superchargers will it work or is there something I need to do the engines to make them work. Thanks for any help

There are other much more qualified, but here is my $.02. I think the freeze plugs must be changed to brass and the head gaskets to a marine gasket. The stock cam is wrong for a wet exhaust. There may be other issues, but these will get you started.

Dail Bennett

I would be worried about having to change the exhaust more than anything, considering its a taller block.

Read

http://www.offshoreonly.com/forums/s...ighlight=zz572

and

http://www.offshoreonly.com/forums/s...ighlight=zz572

That sounds like really low performance numbers for that much motor. Deffinately have to hange exhaust. Block is almost .5inch taller Cam is way to aggressive for wet exhaust. Change to marine type. Put some big oval port heads and you will get more power with less cam. Then You won't need to whipple. Just my .02 worth of analysis.

Try this link, Jeffery is the guy that started OSO, He put a lot of info together here.

http://www.offshoreonly.com/forums/s...15#post1371715



Cougarman

And they get closer together too.

Standard block is 9.800" from centerline of crank to the top of the piston deck where the head sits.

Tall deck is 10.400" from centerline of crank to the top of the piston deck where the head sits.

So those dimensions are traveling at the same angle the piston runs. Buddy of mine put the tall decks in his Sonic
with 35" centerlines from engine to engine with Gill manifolds
and Solid fully welded Stainless one piece elbow and pipe all the way out the transome and didn't have to change a thing.

When your traveling the angle your piston runs I'd be surpised if your dimensions change more than 3/16 of an inch on each side,.........both in hight and width.

And there should be enough room in the exhaust hole cut outs in your transome to compensate for all of that.

Cougarman

Tall deck is 10.20" from crank CL to top of deck for a total difference of .400"

Larry

62 Bel-Air 409

260 Eagle XP HP500EFI

2002 Corvette M6 Coupe

I would really like to thank everybody for the info its been very helpfull . Does anyone know how Jeffs boat held up after he worked out the bugs :drink:

The problem you usually run into is not so much the added height,width of the block, but also the heads. The aftermarket heads move the exhaust ports up to help the exhaust flow. By moving them up, they also go out. Some move almost a half inch. Combine that with the added block width and some won't fit.
Goin nuts: As you know, I am very familiar with that boat as I built the 502's in it and did all of the service work on it for years. I think you may have a problem with the current exhaust and the 572's. I doubt it will fit. You may have to change the exhaust to make it work. With all of the changes that need to be made to the motors and changing the exhaust, I don't think it makes sense financially. Give me a call if I can help you in any way. I may be able to put something together for you that will make the power you are looking for and not cost any more than the 572's, with a warranty.
I have a deal on some 540ci/600hp.They are complete running motors with all new, name brand parts for 13,500. We can make any changes to them to suit your needs. Give me a shout if you are interested. Hope this helps, Eddie.

Eddie would I be a head of the game just to redo whats in the boat if so what would you recommend would like to keep the fuel injection if possible if not its not a big deal . I would think it would less money to redo whats there just wondering what its gonna take to get around 700hp . the 572s are 660hp on a dyno

700 out of a stock 502 would probably cost as much as the 540's eddie is talking about with a lot of stress on that bottom end. Just my .02