Once again 454/330 mods.
 

My friend is looking for reliable 454 combo. This is what
we have come up by now. Crane139731 cam, Air-gap intake, 1410 750carb. Edelbrock O-port marine heads,
stock rods w/Arp bolts, Speed-Pro H426CP hyperetectic
pistons, Arp-bolts for mains & heads, what about exhaust-manifolds, Kodiak or, EMI aluminium? Boat is equipped w/merc´s cast mufflers to 4"thru-hull´s? It
seems he has to get rid off them, to make any power?
Are there any reasonable priced good flowing mufflers,
which would take the noise down without sacrifacing too
much power? Boat is 24 ft. Mach 1 1988. It ran 54mph
on stock 330/4500rpm w/23" Mirage. New engine should make around 465 to 480hp, anyone w/similar
size boat/engine combo, what wuold be estimated top speed for this one? If there are mismatched parts, or
better=an en-expensive way to make this power, suggestions, please?


S-24

engine mods
 

I was in the same situation you are in. By the time I added it all up it was cheaper just to go with a 502 marine long block. The block has the forged crank and good pistons in it already. I do use that 731 cam, merlin intake, gold roller rockers, MSD ign, Imco exhaust. It makes 512hp on the dyno.

Probably the only suggestion I have is to use theH693CP piston instead of the H426CP. The compression ratio is a touch higher.And yes, I've used them before with very good results.

S-24

Take a look at our new in-tube silencer that we sell for $250/pr. It will quite the engine with out giving up any power. Our web address is www.hpisilencers.com and you can check our products out in the classified section here,

Thanks
Dan
1-866-843-1900

Hydro Power, Dyno is sick of dealing with his factory switchable exhaust and your products look like a good way for him to upgrade. You might want to drop him a pm. He's in Jupiter Beach for the week but I think he's got a computer with him.

Thanks Crazyhorse