Tuning questions

[genolan]

I have a Backdraft 408 making 520Hp so the engine spec sheet says. The engine has vic jr heads and intake along with a holly 770 street avenger carb.
Other engine spec's are unknown. The car pulls and runs much better with the changes I made to eliminate the Bog.

I had some pretty severe bog and changed the squinter from .25 to .35 along with switching the cam from a green to brown. This took care of 95% of the bog with only hard acceleration from 2500 rpm giving a slight stumble(no black smoke at all when nailing it). Exhaust pipes inside look almost black.
Carb is stock with the following
pri jet 72
sec jet 75
pump nozzle increased from .25 to .35
pwr valve 65
secondary diap spring silver (vacumn secondary)
idle set to 1000 rpm

Issues?

Popping out of exhaust when at steady state 2500rpm and also when deceleration.

Should I increase squinter from .35 to .37 i'm trying not to go over this since i'm not comfortable changing the pump to 50cc.

I'm really enjoying playing with my new toy even though it's freezing out.

I haven't had a chance to check vacuum or timing yet.

Any ideas or is popping normal