22 DAYTONA

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Raylar

Guys be careful here. Read the fine print. the GM crate motors have warranty statements that say "Not intended for Marine USE! This means that they are not set up properly for marine use, such as freeze plug material, camshaft profiles, some clearances, and others. Why risk the one year warranty on the GM crate motor to save some small bucks. Even if you take the motor down and bring it up to marine specs.. it won't past muster with GMHP on a warranty claim.
I know lots of OSO'ers have had some bad luck with rebuilds and reworks on their 454's and 502's around the country with those so called "expert marine engine shops" but thats not the engines fault. For those who don't know GM Powertrain distributes complete long motor and short block marine built new engines complete with 1 year warranties for very ecomical affordable prices for 454-502 replacements in various horsepower levels from 350- 450HP, about $6K from your local GM Powertrain distributor. Do some simple head work and cam change on these new motors and you will easily see 500+HP.
Mefi-burn has reprogramming software for the Mefi3 and Mefi4 units out there, but reprogramming is not simple and safe always, unless there is already a proven calibration program for your exact engine leave the reprogramming to knowledgable experts like Mark at Precision Marine in Louisiana, "Caus its so dam easy to SMOKE a valuable marine engine!"

Regards,
Ray @ Raylar

Amm

You know way more about this kind of stuff than I could ever know, but I can explain why people(at least me) look at GMPP crate engines for marine use.

For me its the ZZ4, which has the same fine print of "not intended for marine use". Many boat racing organizations have a class now that mandates a stock ZZ4. The ZZ4 can go WOT for hours in these jet and v-drive races. http://www.hotboat.com/forums/showpo...9&postcount=46

Perhaps boat racing is closer to car racing than normal boating use? Or maybe the ZZ4 is an exception?

Pat McPherson

Sure Ray, you are absolutely right about buying the "marine version" base 502 engine.
There is no better deal than 1-800-runsnew for a base 502.
But how to piece together a 500+HP fuel injected engine without breaking the bank?
I think this is the question within this thread...

BY U BOY

Marine pwer does exactly what you want done with the
ZZ502/502. They also have a 530 which has a big cam and they also offer the ZZ572.

Pat McPherson

You got a link for us?

handfulz28

Pat, are you a carpenter? You hit the nail on the head...

BY U BOY

site is currently down.

http://www.marinepowerusa.com/

handfulz28

Actually trying to think specifically about what I'd want, I've come up with this:
A fuel injected version of a Merc 400/420/440. Basically a hot-cammed 454 with an EFI setup. I bet that Marine Power 454 PFI with a hot cam and aftermarket exhaust (not even headers) would be pretty darn close. I don't see how anyone could beat that for a warrantied, "crate" engine in that power range...

Raylar

I don't pretend to be a 454-502 engine expert and if you really want to know from some guys who know talk to Tom Fileman at Flagship Marine engines in Punta Gorda, Florida, he's the GM Powertrain master marine distributor and he's put together a lot of GM Powertrain marine engines both carbed and efi in your horsepower range and they know exactly how to do it reasonably priced. You might also talk to Mark at Precision, Tyler Crockett and Bill at Victory marine in Texas as well as many others here on OSO who have for many years now put together many 500HP reliable 454-502 marine engines that didn't break the "piggy bank" Talk to the experts, they know how to do it right and "tight" when it comes to these engines!

Regards,

Ray @ Raylar