Just finished mine, very happy.
Engine is a .30 over 360 with a Rod Bloomer 4.125 crank/kit to equal 420 cubic inches.
Compression is near 10.5:1 eddy heads gasket matched and some bowl blending/Hughes roller rockers.
Hydraulic roller cam .573 lift around 250 @50 duration. Eddy Super Victor intake with a Holley 750HP that flows 820.
904 with 2.76 low gear set, T/A manual valve body and a PTC converter that flash stalls right about 4000 rpm.
4:30 gear is a little too much, Going with a 4:10, maybe 3:91 as some street us will be in order.

Best of luck!!