Repowering a 98 Eurosport 233 sport.
Mark IV block, scat rods, alum rect port heads 225/188 valves, domed pistons yielding 10:1 compression (running 93 octane), air gap intake, 1410 carb, electric fuel pump, Imco power flow exhaust with SA risers, 222/226 114 LSA Hyd roller cam. My cam grinder says I should be pushing 500hp but cam sounds to small to me?? Since I'm running shorter risers and captains call reversion was taken into consideration. He swears the motor will still make good power but I'm concerned about that cam grind?? I want dependable power to 5200rpm and at least 450hp.

With that cam, I think youre leaving a lot of hp on the table. I would guess you might make 420hp or so.

Get longer risers and bigger cam. Otherwise, no reason to have to run that compression. To have to run 93 octane for such a mild motor seems like a waste to me...and maybe a hardship if no 93 octane on your body of water.

Edit in: since a switch to aluminum heads, why not some good aluminum oval ports ?

My opinion. Other's may vary.

Who is your cam grinder?
If the cam was custom from a knowledgable source, he specified it that way based on the data you provided him ( engine and boat data )

It has been my experience that good custom cam guys know what works with what you have and how you use the engine.

Whats the lift on the cam?

Not sure I'll have check I can't remember what he said on lift.

Oval port is what I was leaning towards but builder said only 20cc bigger on the sqaure ports and it would flow better on top end

If truly 10:1 compression, I'd agree that cam is too small

How does compression ratio affect cam sizing/selection?

Dave's Radiator Shop ?