Bad distributor cap = backfire (pics)?

[Rick Parker]

It looks like the tip of the rotor might be contacting the Brass towers within the cap. The resulting grindings or "DUST" may be allowing cross firing within the cap. Replace them both, whether they warranty them or not.

[Gaz64]

Too much endfloat or mismatch of parts.

As others have said the ground up brass dust is your crossfiring.

[RICK LAKE]

Looking at the spark fire area, IMO it's too high, should be in the center of the cap terminals. End play of the distributor itself my be too loose and have the shaft slide up and down. Crack in the center electriode housing. The rotor burnt mark is not centered which tells me that you could have the wrong rotor for your setup, it happens. Is it possible that there is a problem with the petronics? check with some of the threads on here about problems. Rick L. Ps that rotor is also an emmissions rotor reason for "E" on the plate and gives a wider gap and has a wider end for the terminals. Look for an Accell cap and rotor or sorenson aftermarket.