Have a person slowly open the throttle by using the stick while you look down the carb. The point just before the secondary opeing will be lean. Don't run for a sustained period of time at this throttle setting.

I went back and reread some of your old posts. If your jets are 78-82, that seems about right. Stock jetting varies from 75 to 79. Stock power valve is a 6.5. Because your engine has a roller cam and is fairly low on vacuum it doesn't surprise me that it needs a later opening power valve. Holley generally has the same power valve front and rear. I know you're getting tired of this, but I would try 4.5's front and rear. 5-7 lbs is good for fuel pressure. Check your igniton curve. 14 initial, 34 total, all in by 3000.

If you're worried about a lean spot, do a plug check at the rpm just before the secondaries open. Good luck.

Also if you still have that vacuum leak, it's really messing with your part throttle response. I hate leaks. I still use the tar-like Permatex on a lot of stuff so I don't have to go back and do it again.