A 366 with a 4 inch crank, 6.535 rods and a 3.968 bore 1.64 height piston in a 3.970 bore would make a 396 tall deck. With a 10.5:1 static compression on stock p nut port heads, HEI and a 600cfm 2 barrel blow through EFI? I'm betting close to 500 tq at the wheels around 1700 rpms. On 8.5 psi? 800tq. Need to find someone to make the Pistons. I've already checked to see if a 4 inch crank will spin in a 366. It does. No clearance issues. May have to clearance the bottom of the cylinder walls for the rods but I doubt it.
spend a grand and get MAHLE pistons. The best piston build quality, engineering, and metallurgy on the planet. The MAHLE piston ringlands are reinforced. Get your rings on properly by using a ring application tooL. Measure your bore all the way down and at the top. Gap accordingly. If your bore varies by only O.OO2" your Ring Gap shall be off by up to O.OO8" even If it was dead nuts at the top of the bore. That leads to broke pistons. Also use the 4 gap position method. Also put the pistons in correctly and the rings facing the correct way. Lol. sorry so long, this is for everyone out there. In case for understanding a piston install. Also rebalance your entire rotating assembly. And smooth all the sharp edges on the tops and your spark plug threads with the heads off for more added detonation resistance.
@Bladen Rexroth I once threw a 350 together out of a bunch of stuff I had laying around. By the time I honed the block enough to clean it up the piston to wall clearance was like .015. Surprisingly it ran very well and didn't even have any piston slap or burn a drop of oil. Obviously it's not recommended But I've found older Chevy engines to be pretty forgiving with tolerances.
