Craig,

You may want to go back to 4:56 or even 4:88.
I have a buddy with a similar combo to yours,
but with 4:30 gears.

His motor is a 408 stroker, Edelbrock aluminum
heads that have been ported, a much bigger carb
than you run, compression similar to the 11.5
you are looking at, similar stall convertor, 904 trans with low gears.
Car is somewhat heavy at around 3400 lbs (67 Cuda FB)but
it's best runs have been 10.98 @ 121 at Vegas
and then 10.92 @ 123 at Fontana CA