What's wrong?

I realize it's hard to diagnose over the internet......

I'll try to give a much info as possible.
72 318, is making 365 hp on the dyno. Fresh build.
Crackling and explosions out the exhaust.

I thought it was too much fuel pressure, regulator didn't fix the problem. I don't have a gauge on it, I backed off enough to where it shouldn't even run, still runs and crackles, muffler explosions. Etc.

Checked firing order several times, timing is set at 16 deg. Has FBO ignition with advance limiter plate. Worked fine on the dyno. Did not use the FBO ignition on the dyno though.

All plug wires are sending current, checked with timing light.

Carb is new 1906 AVS2 650 cfm.