Reply to "Closed Chambered Heads"

If you had 9.3:1 with open-chamber heads, you probably have domed pistons, at least slightly. If so, they can often be made into flat-tops with a lathe, as long as they're not hollow-domes such that the cut thins the piston crown too much. But if the block's been squared, the heads surfaced and all that, the final clearances might be such that you'll need thick composite head gaskets or cupped pistons to get your compression down to 10:1 or slightly lower. A big-duration cam will help reduce pumping pressure for 91 octane fuels without ping/knock. CA gas is arguably the worst in the US for these games incidently. The heads are fine (i assume they've been cut for a Boss valvetrain?). All you'll lose over 2V Aussie heads is some low-end torque due to your 4Vs having such gigantic ports. Great for top end stuff or stroker motors, though. As for an intake, Edelbrock's dual-plane Performer is the most poular unit on Panteras, matched to a 650-750 carb. The smaller the carb, the better the driveablity & fuel mileage, too. An open-plenum intake will make the top-end bias of your engine even more so IMHO.