Do you have the mounts or are you going rail kit?

If your tryin to just buy and drop it in go for a rv motor there usually built better look up block numbers and look for a 4 bolt main casting

Oh ya forgot about the peanut ports they were on the tbi motors forsure not positive what others

60 might be high with a stock 454 and alot comes into play boat weight how tight your pump is what impeller ypu have im not too knowledgable on pumps theres others on here that are tho and for the motor id look for pre smog and low miles hard to come by but it happens check out what engine casting numbers and head casting numbers have what and go from there in my opinion i would look for a motor with a decent set of oval port heads that has a 4 barrel on it then run an edelbrock or equal high rise

This might be a good starting point if you're willing to collect the needed parts and have someone do the machine work needed.

I wouldn't bother with the heads but you really can't go wrong with the other pieces for the price.

http://www.socaljetboats.com/random-boat-parts/2-bolt-454/

This is very true ive had to pull my motor a few times till i did it myself then had to pull it again to move tanks shoulda thought that through a bit more

I have a complete bbc 402 from pan to intake and harmonic balancer to flyweel and glenwood 4 point mounts along with it. Pretty sure it needs to be rebuilt, motor was seized when I got it but I got it to run somehow. Low compression in 2 cylinders.

im not realy interested in doing a rebuild on a motor. i'm looking to purchase a used running engine. i don't mind having to change gaskets and cleaning it up. i just dont want something thats underpowered. i guess i'm looking for the best stock motor available. i just want this thing running as soon as possible. something that will respond well to a simple intake manifold and cam change.

Just look for something you can hear run. If you are going to change the cam, a decent cam will need good springs, any cam that dosent need a spring upgrade isnt gonna be much better than a stock smog cam. Or find a short block, put some 781 or 049 heads, comp 280 or 292 cam or similar (with good springs), single plane manifold, headers. Jet boats=cubic dollars 

Daniel

Not all Gen V & VI are roller. The roller provisions are in the block. Roller is the way to go though. MK IV & Roller

Daniel

  Here are specif years you might consider (Gen IV 1965-1990, and Gen VI in 1996) I personally run a '74 454ci bored to .60 over had no issues after rebuilding it.

The middle post is tbi gonna have peanut ports on it

I have a 20.5 Caribbean mini day cruiser. Its a bare hull project. I need advice on which engine to run. I plan to run a BBC. I would like to find a low buck 454. I'd like to find a used 454 from craigslist. which model 454 would be best in a boat? from what year? which type of vehicle? RV? Truck? I hope my question makes sense.

Buying a used engine is kind of a crapshoot, and putting a used engine out of a car, truck or rv usually means one that would have cast pistons. 

A later model, Gen 6 engine should have a roller cam, but out of a truck or rv will almost definitely have the tiny, "peanut port" heads.  Also a Gen 6 block (unless you found one of the 454 crate engines) will not have provisions for running a mechanical fuel pump, so you would have to run an electric pump. 

I will PM my number to you so that I don't have to type an entire novel, but can give you a little more education that may help you decide which way to go.