have a listen

Sounds like an ignition problem to me. I would be inspecting cap and rotor. Might also be a phase problem, where the rotor is between two cap terminals. Has the wiring for the distributor pick-up coil been modified? Is it an HEI module conversion?

How do your cap and rotor look? Is it a stock distributor?

Its a petronix dist. cap and rotor look brand new.

Looks like the cap and rotor are ok at this point.