FWIW, I had a friend install a Mallory Unilite Distributor. It worked for a while but then started having random stuttering & misfires. We found that the breaker plate had no ground wire....it was expected to ground through the 3 ball bearings that it rotated on. We added a ground wire from the distributor body to the breaker plate and it has run correctly ever since. Might be worth checking if you have a unilite.