usually the block is damaged..sometimes reduced to doorstop material....if he's lucky and it's not tell him to buy a lottery ticket....or at least some good forged stroker kits !! can make them 496's with out to much...

The block may or may not be hurt. Chances are it is hurt. If that thing came apart at any kind of RPM it might have cracked the cylinder. If it is just knocking you are good! Well not good but you know. I would agree with the 496 upgrade package. We are doing a set of 496 upgrades with eagle kits 990 iron heads and about 9.3:1 compression. Also we have some BMS custom cams built for this package. We should be on the Dyno in about two weeks with them. We are hoping to see around 600-625hp on 89 octane.

I would guess it'll take 600+ per motor to get that boat to 80. You won't get there with iron Chevy heads unless they are heavily ported and big cammed. You're better off going with blowers on a fresh bottom end. Less money in the long run.

I'll throw in my opinion. I would also estimate a need for about 600hp a side to see 80mph. I'm not at 80 with blower motors on a 31' Cigarette!

I would say take the engines to 496 and add blowers and you will for sure see 80. Just be braced for the fuel bill.....

468 ci 650hp blower motors took my Bullet to 86 with labbed 30s..If that helps any...