What gm head castings and valve sizes?
What cast iron intake?
What cam?
With 9.0-1 to 9.2-1 CR does it take to make 450hp with a .030 over 454 mark IV

I will be running emi manifolds wet risers through hull. And a 800 Holley DP. Or is this possible? Just don't want to build a pig. I have the block/ rods/ crank ready to go. Just need to know what heads so I can order my pistons.

Thanks Aaron

Ill make it really easy for you. Engine masters just did a 454HO buildup for a marine app.

Stock 454 shortblock, 236/242* hyd roller cam, dart 310 aluminum pro 1 heads, dart single plane intake, holley 1000 hp 4150. Engine made 525HP@5600RPM, and kept pulling to 6000 making power. 517FT lbs at 4800.

Only thing I might do different, is a little less cam duration, and a little more lift than the one they used. That should bring the peak HP down to around 5300-5400.

"330 on roids" did 460hp @ 5200 for something a little milder/cheaper

in my opinion,the cam selected is good,prop the boat to spin 5500 rpm,and u have a winner

Aaron,gm sells a crate motor,i think it is 425 hp 454.go on the gm performance website and check it out,i think with the parts they are useing,and a little bit more cam,450 is easile achieved.

Is there a link or is possible for you to post the article? I'd like to read this.

good option also

http://www.chevyhiperformance.com/te...ine/index.html

Wouldn't an old Merc 420 spec engine with a nice hydraulic roller cam get you in the ballpark or a little more?? You could still use the GM rectangle heads and save $2000 over going with aftermarket heads. If you were going after market heads I would also go with the Darts.

Thanks for all the response guys. Only thing didn't want to run aluminum heads or intake. Salt water eats them up.

9.6 comp

.30 over 454 (365 mag origin)

Dart 308's

Comp XM-270h-12 cam

AirGap intake

HP 500 Carb

IMCO EXHAUST MANIFOLDS

453 HP @ 5500

505 TQ @ 4300