MSD Cap build-up

[Blas]

Would be interesting to know if this problem has been there since day 1 on the car or if it just started when you replaced the cap... If it just started and ran correctly before, you may have another issue lurking somewhere... I would assume that the caps all come from the identical forming press design molds so the alignment of the contacts and the depth of the contacts are uniform across the manufacturing process. Same holds true for the rotor. No possibility you replaced the rotor with the wrong part? No carbon burn marks around the center carbon post that I can see on the photo. Did you bend up the contact on the rotor a little to insure good continuous contact with the caps center button? I remember reading about a problem with some caps sitting too low and the gap was then too big at the 8 outer contact posts. Any rust or corrosion on the distributor internals? Are the Magnetic pickup wires secure and not too close to a plug wire... did you make any modification to the routing of the wires between the distributor and the MSD box to maybe clean it up since you were working on it? Good ground on the MSD box? Good secure power supply connections on the box? The ignition is usually wired as the switch for an MSD box...they are notorious for spreading power issues...