SOX

I am looking at a boat with a carb. 454. The dealer is going to look up the #'s on the engine to be sure of the horsepower but they are advertising it as 385hp. But I think it may possibly be a 330hp motor.

Either way, can I get a builder to build it up to 525hp or better and still be reliable or would it be more cost effective to just buy a new motor? I would like to be able to just have an engine builder take the existing motor and build it so reinstallation would be simple. Any estimates on how much it would cost to do this would be appreciated. I am trying to figure in the upgrades I would make to the boat before I make an offer.

Thanks,
Rob

t500hps

taking a 330hp 454 to 525 will take replacing EVERYTHING (crank, rods, pistons, etc). Your answer depends on whether you have the Mag or the MPI.

tcuda499

he states carb...so no mpi

PJDiesel

I think he meant mag or 330.

Thats the deciding factor. I went from non mags to MAGS rather than replacing one non mag last spring.

HUGE difference between the two, non mag is all cast internals with small oval port heads and cast intake.
MAG is ALL forged internals, large rectangle ports and aluminum intake.

Going from 454MAG to 420/425/525 is all simple bolt on stuff, going from 330 is a waste of time, start over with 500EFI or better at that point.

SOX

So if it is the 385 hp then it is a mag and not too big of a deal to pump up the hp? This bot has just under 300 hours on it so it would be nice to keep it.

PJDiesel

365hp if it's carbed

Griff

It is simple to tell the difference between a 454mag/365hp and a 454/330hp. The intake manifolds are completely different. The 454/385hp were EFI's or MPI only.

BTW, some of the early 454/330hp's were called 454mags. What year engine are talking about???????

SOX

The boat is a 96

Griff

If it has an aluminum high rise intake, then its a mag engine. If it has an iron low rise intake then its a 310 or 330.

blue thunder

Looks like a 365hp mag to me, but the angle is tough. One thing I see right off is the port riser spacer is leaking. Not good usually. What boat are you looking at Rob?

The expensive part of building it up whether mag or not is going to be the exhaust. That is the same exhaust my 365hp mags came with and the spacers are leakers and then valve head droppers. Also to make power you need better exhaust. Once you have that you can do a cam and better carb and some head work and make close to 500hp for probably another 3g.

Dave