Power Valve Size

[01somta]

I bought a motor about a month ago and the guy suggested getting the carb rebuilt. So I got the carb back about a week ago and the shop rebuilt it back to stock specs. I was wondering if with my motor specs I could get an idea of the correct or close to correct power valve size? The motor is not in the car right now and on an engine stand, but I would like to get the carb close to ready as possible.

502 Gen VI 4 bolt main, 9:1 CR
Melling hv oil pump
Crane solid roller p/n 168601 cam .615 .636 246 254 dur @ .050,
crane solid roller lifters
GMPP 12363400 Aluminum Rectangle port heads
GMPP 12361323 1.7 alum Rockers
Edelbrock victor jr 454-R intake
Crank Ext. ballanced, nitriated, crossed drilled gm p/n 10198922
Rods Forged 4340 Steel
Pistons GM P/N 12533507 Forged Aluminum
MSD Pro-Billet Dist.

[ZZ4Blazer]

Per holley's website, if I remember right, you need to check the motor vacuum first. At op temp, if auto, in gear, and check the idle vacuum, then use a PV that is half of that reading.

Like 10" of vacuum, use a 5 power valve. Seems to have worked pretty well for me.