dna

I have a 92 Sleekcraft with a 454 (non mag - it is 330hp) with bravo1 drive. About 1.5 years ago the engine failed (basically an exhaust valve snapped and smashed through a piston). The entire bottom ends needs a rebuild. I am not that mechanically inclined - the boat has sat since. I can tinker but rely heavily on youtube, goggle, and forums.

I am now starting to rethink on rebuilding this boat. My questions:

1) can I use a car 454, 496, and/or 502 and put into my boat. Would each work with my setup, or just the 454. I understand the camshaft on marine engines gives it more low end torque - is that all that I would need to swap. Can I use the cat camshaft.

2) I assume I would need to use my existing exhaust manifolds - are these basic swaps if I got a car 454, 496, or 502? Or would only one or 2 of these work. Would I also use my marine intake manifold, or would I use the one of the car engine.

3) would a car engine (454, 496, 502) bolt up to my bravo1 drive? what would be involved?

I found a 496 out of a 2004 truck with 200,000 kms for 1k$ asking price. Basically wondering if this will be a relatively easy swap, or would this be very complex.

flashgordon

well,,first question is your 454 a mark 4 or a gen 5????
i think you could use a car 454, but it may only be a 2 bolt main block
i am pretty sure all marine 454 are 4 bolt main block.
the 2 bolt main would work, but the 4 bolt main blocks are stronger.

i believe a 454 496 , 502 would all bolt up to your bravo,,,,''believe''
i think your exhaust would work on any big block chevy
i know there is a diffeerence with some 502 gen 5,,as you cant bolt a fuel pump on them from a mark 4. you must buy a merc adapter.
mark4 are pre 1990???? i believe,,
i guess big question is do you want to get it running and sell??
or keep it??

200,000km is 120,000 miles??? hmmm,,on gas engine in truck...
i would want to hear to run for sure..

phragle

iTrader: (3)

Sure you can, its just going to cost you $10 to save $5 , and do you really want to take an old tired truck motor and ask it to spin 5000 rpm under heavy load for extended periods of time??

You will save money, time and frustration spending more up front and doing it right.

Helmwurst

For a $1000, you should be able to have your heads worked over and the block cleaned up. Throw in another $1K, for rings, bearings and some gaskets a few hundred more for a used piston or two and some assembly. For around 2500 or a little more, you would have a fresh rebuilt engine vs a half worn out truck motor with who knows what its life has been. 1 or 2 other choices, buy a GM crate engine from an online retailer or a rebuilt Jasper engine or other rebuilder. My 2cents worth

Blueabyss

The Manifolds you have will not fit the 496. And manifolds are expensive. Next thought if you rebuild or replace the 454 or 502, The manifolds may not be any good and could toast your new motor in a few runs or seconds. The 496 you are looking at may be almost whooped already and then you would be flushing 1k down the toilet plus having had to buy manifolds. Best Bet is either buy a running takeout out of a boat or have manifolds tested and if good get a long block 454 or 502. I think the 496 is going to cause you multiple headaches since its not a marine setup. BTW the lack of replies to your thread is due to the multiple variables you have listed and most people , like myself, have looked at it a couple times and thought jeez where do we start.. On another thought what size is the boat?

Chris

oconnor marine

i been rebuilding engines and replacing engines for 35 years. My conclusion is buy a new marine base engine. Do not buy a reman.