I'd like to drag this topic out of the archive because I'm having the same problem with my T-Bird. Last year, at the Keystone Natsionals, I noticed a misfire towards the end of the track (probably 7000-7600 rpm.). I suspected the RPM limiter might be the problem so I replaced the 8000 "chip" with an 8200 one and it seemed to fix it. This year it started to act up again, and I "fixed" the problem with a borrowed MSD box (7AL-2). I then put the original MSD box back in (was misfiring with a new box) and the problem came back. I reinstalled the borrowed box but this time it didn't help. I just bought a new pick up for the distributor (Old Chrysler Prestolite) which I hope will help. I also bought the newer type spark retard so that I can try the crank trigger again. I used to break starters with the old spark retard. This is really annoying me because I lost in the fifth round at the Div 1 race at Lebanon Valley by .002 seconds. I would have had a bye run into the final. I can't really test it without going to the track. I read your "fix" (sheilded leads) but was wondering if perhaps a weak magnet in the pick up might make the system more sensitive to noise. I also have a one wire GM alternator mounted close to the distributor, but ran this way for years without trouble. One other thing. The coil (MSD Pro Power) is mounted on the firewall. The car had a BB Chev. in it before I got it so the coil was close to the distributor. I checked the resistance of the plug wires and found that the MSD wires had about 100 ohms per foot. The coil wire was a Moroso wire which has about 1000 ohms per foot. That wire is about two feet long. I'm guessing I didn't have enough MSD wire for the coil wire so I used a wire from the Moroso set. I used to run Moroso wire all of the time and never had trouble. I did change the wire to a slightly shorter one at the track but it didn't help. Maybe I should mount the coil closer to the distributor.