Jeff,
I looked up that zz430. It has 9.6:1 aluminum heads "fast burn" they call them. based on zz4 motor. The "hot" cam is a 218/228/112/.525 and it peaked at 5800.
750 Holley, single plane aluminum intake.
Remember, you'll need after market exhaust to get those numbers.

If you wanna email me feel [email protected].

DAVE

Here are my dyno sheets for my n/a sbc build that cost me under $4k from start to finish. I got just over 400hp on the dyno and that is before I did some bowl work, carb change and spacer which gave me 400 RPM more. I would guess I am putting out about 430-440hp.

gonna be pretty difficult to get those power numbers from a fair mannered 350... might squeeze it out of a 383 or a 434 might be a better bet...

i am currently at right in the neighborhood of 380 crank hp on my merc 350.. the only thing stock is the rotating assy... my motor makes peak HP right around the 5200 mark.

in a nutshell... proaction cylinder heads (non cnc), comp hydraulic roller, smallest they offer for a strictly marine setup (XM264HR), complimenting valvetrain, stock exhaust manifolds with imco risers, rpm airgap and a holley on top.. fired by an MSD digital 6+ box and pro-billet.

i do have the XM276HR in the toolbox awaiting installation... i will have to wait to verify actual numbers on the dyno when i do it but i estimate 405 - 415 @ 5500 - 5700 rpm... at the crank... subtract roughly 7 - 10% for effiency loss through the drive...

when you get into these numbers it really is a good idea to look at aftermarket exhaust... the stock merc center risers are right on the ragged edge in the scorpion territory... i would bypass the aftermarket manifolds and buck up for headers...

I agree, those Proaction heads are the way to go, I tried Dart Iron eagles and the Proactions gave me better flow and almost 2 mph more top end.