Baffled

[Track Junky]

I ran my car at Sonoma and everything was fine. Did a rear gear swap but didn't drive the car till I installed new brake pads.

Problem......car is hesitating under load. I can goose the throttle with car in neutral with no issues but when I drive it and open the secondary's up the car is hesitating under load with slight pops out the exhaust.
So far I have torn the carburetor apart twice, replaced power valve and accelerator pump diaphragm, checked float level, checked and tightened my fuel lines, replaced plug wires, replaced dizzy cap(had a crack in it), and checked a few of the plugs to see if they were fouled.

Not sure if its a lean miss or electronic.

Any other suggestions?