Required internals for 6 psi?
 

I'm piecing together some 454/468 motors with forged pistons. I read somewhere that for 90/100 hp per piston, you can stick with stock internals(??). Forged pistons are a no brainer (probably set these up with 0.005" clearance)...went through the hyper-u-cracked it experience on a naturally aspirated motor...wasn't pretty. Will shot peened stock rods and a standard cast crank work with 6 psi (intercooled) efi boost? I plan to use wide band O2 sensors and EGTs so I have a good grasp on what's burning inside. Also, what about the standard mercruiser coupler...and Bravo ones hold up to 600 hp...continuous? Obviously, a forged crank is the way to go, but is it necessary with mild boost and just over 5000 RPM?

The boat is primarily just a cruiser with the periodic grudge race for a few minutes. No poker runs for me...can't afford the engine builds let alone, the fuel costs! I thought twin 400 hp motors would do...the addition continues with turbos!

The stock rods, as long as they have 7/16 bolts, not 3/8, will work just fine. I would in put a set of ARP bolts. The rods must then be resized. However, I would not even try with a cast crank. You can pick up a used forged crank pretty cheap. You can also get a new Scat for about $600-$700. The coupler and drive should be fine as long as you don't drag race it. Hard acceleration will kill a bravo behind a blower motor every time. Eddie

Thanks Eddie.

Absolutely no plans to drag race the boat...being weighted down with A/C, gen set, TV....bunch of heavy stuff with normally 10 people on the boat. Just looking to have a decent top end in the rare situation when a stock weisenheimer pulls up to me. Besides, these center consoles are getting faster down here in South Florida and that is embarrassing if a bunch of fishing poles blast by you. Hasn't happened yet, but I won't leave it to chance!! :evilb:

I guess I should rephrase that. Not drag racing, but hard acceleration will kill the drive and coupler. Being past by a cc is almost as bad as being past by a deck boat.:D :D

Hey, I resemble that remark! :D

We're all laughing, but it has happened to me before.:D At least the guy wasn't flipping burgers when he past me at 95 mph.

My joke is to put both the bow and cockpit tables out and have kids sitting back eating PB&J sandwiches waving as we go by! :evilb:

But, I don't go by near 95 MPH!! :eek: The jelly would splatter all over the inside of the boat! :D

That would make a mess, wouldn't it.:D