Good quench isn't of much value if the C/R is less than 9-1... It's more work but I would use a shorter quench pad & mill the head & block as needed to get quench & 10-1+C/R

Well looks like I need to go with the KB146 as Ron originally suggested then.

Ron's 63 obviously runs hard, he's got a good strong combo, chased the details to make it right & the car performs...

FWIW, I had 902 heads on the 440 in the challenger when I first put it together.
I used the TRW sixpack pistons which are flat tops with eyebrow valve reliefs. Block was decked .040 and heads were cut .015. The .040 cut on the deck put those pistons at zero deck height. Felpro .039 gasket and CR was 9.8:1. I ran the 484 cam with performer RPM manifold and 770 street avenger carb.
3.91 gears with 28" T/A radials netted a best of 13.19 at 108.5. Those tires wouldn't hook and best 60' was 2.10, so it had 12's in it for sure with a decent tire.
With the lousy quench from the open chamber heads, it wouldn't run without rattling on our 91 octane here in Calif. I had to mix in some 110 to get the octane up around 94.

Now I have edelbrocks on it with a sixpack setup. It has .040 quench, 10.2:1, and runs fine on the 91 octane now. Haven't been back to the track with it, so no idea what it would run now. Still has the T/A radials on it.

i posted about the pistons in the race section.there is some V/Pcam info.you have some good info to help now.i hope to meet you some time around town milan!
https://board.moparts.org/ubbthreads/show...e=0#Post4971697