[kevo95]

I have a 21 foot Ultra custom jet boat ,everything is stock ,I was told it has about 280 Hp not cutting it.It has a berkley jet A impellar.i just purchased a A SET OF 454 HEADS JUST REBUILT THE VALVES ARE STAINLESS STEEL 2.190/1.880 THE SPRINGS WILL TAKE .550 LIFT THESE ALSO HAVE A REAL NICE 3 ANGLE VALVE JOB MILLED SURFACES THE THROATS AND BOWLS WERE BLENDED TO MATCH THE NEW VALVES NEW VALVE GUIDES HIGH TEMP SEALS ,the Comp cam Hydraulic .purchased has a lift ,Int 544- Exh 547 ,im installing new comp Roller rockers,COMP TIMING set double roller ,lifters,gonna use Edelbroke Torker manifold ,with 850 Holley Double pump.This is gonna be my first project ,im knew to this site,what gains should i see with this set up.Thank you.Kevin

[BowTiePride]

Which engine are you using? A possible interest for you might be forced induction. Racing boats that have turbochargers on them typically run thier intercooler in the water (cold water from the water you boat on passes through the intercooler cooling it much better than an air to air intercooler could) and research the possibility of running the turbo free-floating (no wastegate valve). Just my $.02
Jake

[kevo95]

It is the stock Chevy big Block 80 ish ,it is covered engine due to kids ,it has the wet log exhaust headers coming out the transom.The boat is a 1989

[BowTiePride]

Gm produced several big blocks (348,396,402, 409, 427, 454, 502 and I'm sure I'm missing ones. Crate one's are also availably commonly 496, 555, 540, 572, 632 etc). You could ditch the emmissions (strip down to bare block and try to replicate the LS6 <when produced, with no emmissions it was under rated at 450hp> by getting the heads, manifold, carb, basically strip it down to a short block and transferr over the rest from a pre 73 BBC) previously stated, when the LS6 came out id was grossly under rated at 450 hp but when emission laws hit it dropped down to 260hp ish (depending on model/package)

[BowTiePride]

Go to www.mortec.com for casting information. What are your goals/budget for this? Any idea on what road you want to go down (high rpm screamer, low end torquer, forced induction, naturally aspirated, etc)