Need fast help brand new 770 holley

I wouldn't start changing things on the carb untill ALL other areas are in tune (especially the timing)

What purple shaft is it? knowing the dur. @50 makes it much easier to determine where the int. timing & curve should be.

Whats the manifold vacuum in gear?

Many people the 1st. thing they do is start jacking with the carb when the real problem is in the timing & curve along with lower manifold readings, I'd take mopers suggestions & get the timing & curve where it needs too be "first", run as much int. as possible, then play with the curve, I strongly suggest getting an MSD adj. dist. that is easy to dial in the curve, there set up like the old chevy point style (weights & rotor) with the springs on top, they are very simple, You'd be amazed how currecting the timing for your cam/intake & vacuum levels amazingly cure all your carb problems LOL.

The avenger carb is set up with a less aggressive metering then your adverage DPers but still gives you the holley perf., plus its a vacuum secondary, They like higher manifold vacuum signals on adverage then a true perf. holley. I still think a 670 would have run better all around, but the 770 should work fine.