Quote Originally Posted by AdamB
Hi, I just purchased a 26' boat with a BBC 454 marine engine. I noticed the previous owner has it set up with an auto Holley 750 double pumper, instead of the proper marine set up.

It is supposed to have 330 hp from factory. Since I have to change the carb, should I stick with Holley, what is easiest way to get more horse power from a marine engine?

I have above the water (thru-hull) exhaust, so I don't have to worry about a big cam causing water reversion.

Is there a specific cam, head, intake, carb set up that would get me close to 500 hp?

I'm guessing it is stock 454, except it has an aluminum intake, and MSD distributor and coil. I have no idea on what type of heads it has but the previous owner said it had the peanuts..THe boat originally had a 502 Chevy, but the previous owner blew that up and replaced with the cheaper 454. So now I'm looking for more power to push the beast along...

Thanks. Oh, I just ordered a 454 rebuild DVD from ebay since this is the first BBC I have owned. I have worked on some SBC 350's though, like changed heads etc.
Like you said basicly use a marine approved carb.
Since you already have the 454 block I would at least up the cubes by making it a 496 with a crank change.
There is nothing I hate more than the "running valves" on a boat engine.
I would run a hyd. roller cam.
Another area that is often over looked is the exhaust valves in a marine engine.
I will not build an engine for marine applications un-less it has Inconel extreme duty exhaust valves.
The bad news is you will spend $300-$350 on the exhaust side.
What is your budget for this engine build?