Mercruiser rebuilding... what pistons?

[simdeg80]

Hi guy's,
i'm rebuilding my 1990 mercruiser 350 cid 260 hp, i've the engine block on the machine shop for re-boring cylinders.
I'm in italy and I want to purchase pistons directly in USA but I would like an opinion on what kind of pistons to purchase: flat top, dished, number of valve reliefs, hypereutectic or forged...
The power what I want to reach is about 300 hp changing rods, camshaft and convert flat top lifters to roller.
I've look at keith black pistons but i've only see automotive use...

Thank's

Simone

 

[Bondo]

Re: Mercruiser rebuilding... what pistons?

Hi guy's,
i'm rebuilding my 1990 mercruiser 350 cid 260 hp, i've the engine block on the machine shop for re-boring cylinders.
I'm in italy and I want to purchase pistons directly in USA but I would like an opinion on what kind of pistons to purchase: flat top, dished, number of valve reliefs, hypereutectic or forged...
The power what I want to reach is about 300 hp changing rods, camshaft and convert flat top lifters to roller.
I've look at keith black pistons but i've only see automotive use...

Thank's

Simone

Ayuh,.... Welcome Aboard Simone,.... This is a conversation you should be havin' with yer Machinist...

Which pistons depends on the rods used, the heads used, the cam used, as well as a host of other contributin' factors...

Buildin' a motor, is pickin' parts that work well together, as a Package....
Change any 1 thing, 'n other choices need to be re-evaluated...

 

[RogersJetboat454]

Re: Mercruiser rebuilding... what pistons?

I've look at keith black pistons but i've only see automotive use...

FYI, Piston's are blind. They can't see whether the engine is being installed in a car, truck, or boat. The factory pistons GM installed would have been exactly the same as what would be used in a truck.

Hypereutectic pistons would work just fine for your application. No need to go forged.
Like Bond-o said, you need to have a conversation with the machinist to figure out what you have. Head CC's, combustion chamber design, quench, compressed head gasket thickness, cam profile, and over all compression ratio you're shooting for are all going to be determining factors which pistons will play nice.