Reply With QuoteThere have been quite a few threads regarding crate motors in general and that 572 in particular over the past year or so, I would do a search for "crate motor" to get some really detailed answers.
The long and short of it is, a GM crate motor would work just fine in a boat. However, GM Performance Parts is very specific in their warranty that marine applications are not covered. Mercruiser engines, obviously, are. So, if you go out and hammer on your $12k engine and it lets go, you're out of luck. That doesn't mean much, however, since the same rule applies to just about any modified high performance engine short of a factory-stock Merc package. All the GM crage engines are solid, and the 572 is packed with top-shelf components so it should last a good long while if you take care of it. Of course a motor like that needs to breathe, so if you don't already have some sort of high-performance exhaust system you'll want to look into some Imco manifolds at the very least, and double-jacketed headers if you really want to make power. Also, the cam in that engine might be too big for marine use, as it has short lobe centers and might try to suck water up the exhaust when you pull the power back. A shop like Pro Marine in LHC or Wilkes Marine in CA could tell you if you need to change the cam or not. If you do, its a roller so all you would have to do is order a marine grind roller cam and stuff it in. Lunati offers all the hi-po Mercruiser grinds in their catalog.
A few years ago I helped a friend get a 502hp 502 for his 28' Eliminator Eagle, and it picked up about 7mph over the stock 454 magnum. He's happy and the engine still runs great. For that type of situation (his 454 dropped a valve and was blown up), a crate motor swap works really well. It isn't such a great option for new boat shoppers. Once you take the cost of the crate engine, add the cost of a new cam, all the gear necessary to marinize a motor (cooling system, exhaust, etc) and then factor in the lack of a warranty it doesn't make much sense.
You mentioned adding a supercharger, and the same arguments could be applied to that as well. Despite what the blower companies claim, slapping a supercharger (or turbocharger or nitrous) to a box-stock big block will drastically increase engine wear. If you don't add much boost, use an intercooler, find good gas and don't beat on it the engine should last a while and will make big power. However, packing boost into an engine with high compression pistons and stock head gaskets is asking for trouble. So, you can add the blower and roll the dice, rebuild the motor AND add the blower for power and reliability at a relatively high cost, or swap in a crate motor. No matter what you do, extra speed takes extra power, and extra power costs BIG $$$.
Dan
