looking for input on performance parts for genV 454 merc
 

I am in the process of rebuilding my merc 454 and just looking for some advice on what other people are doing to them for a little extra performance. the boat is a 1996 baja 208 islander (roughly 21ft) open bow. motor did not really have any problems it was just starting to use some oil so time to go through it. I am looking at different cams but not sure what to go with. I also have been wondering about different intake manifolds and also other peoples input on self tuning efi or if I should just stay carbureted. I bought a set of IMCO power flow exhaust manifolds about a month agao and plan to put them on. as for the moment the boat is all stock. has factory thru hull exhaust. any input would be greatly appreciated. thanks guys!

I have two sest of 500 EFI intakes with injectors, harness, and computer. would make a great upgrade to the 454. They MerCruiser take offs.

Is this a 330hp/350hp ? Not a magnum I assume?

https://www.offshoreonly.com/article...om-stock-power.

Check out this article. Might help you.

Mild performance upgrade is easy.
Significant performance upgrade basically tosses away everything but the block (and the Gen 5 block is the least suitable for serious performance).

Your 330 horse Gen 5 will respond to all the usual tricks.
You do have peanut port heads, so choose a fairly mild cam.
An intake upgrade is also recommended - (the 500 EFI setup mentioned above is for rectangle port heads, which you don't have - but it would technically work)

You also need to decide if you plan to boat in freshwater or saltwater.
A saltwater boat can't use a lot of the usual hop up goodies without you promising to become a dedicated flusher..

An aluminum intake like the Ebrock Performer is a good upgrade, but it won't tolerate salt like your cast iron stocker.

List exactly WHAT your motor and outdrive are right now - as well as whether it is seawater or freshwater cooled right now.
Then list the percentage of saltwater usage you plan.
Then list your intended result - how fast do you want to go, how often and for how long do you want to run wide open. Do you plan on pulling tubes or skiers very often? etc..

<MC

330's never came with rectangle port heads.
The '92/'96 Gen 5 Bravo3 and Magnum motors DID have rect port heads.
The other Gen 5 motors had peanuts.

Do you have a B3 boat?

The Crane 731 or 741 are pretty popular for mild builds. I’m really curious about the Holley Sniper FI unit. For an application like yours (and mine) I personally like the simplicity of the throttle body FI on a normal manifold. The Air-Gap Performer RPM is an impressive manifold, but I just went with a Victor JR on my ~500hp build mostly because Merc puts single planes on their 500 engines and figure they’re smarter than me.