I'm not sure if this has ever been mentioned by anyone else on this site, maybe I have in the past not sure.
This I feel is not a well known issue, but I feel it could slightly affect the operation of these engines at times.
Since the whole distributor moves for vacuum advance, that means that any ground or current path to ground has to go
through a moving surface at all times. Could be the shaft bushings, shaft to oil pump or cam gear, could be at the distributor body and engine block interface
could be at the clamp to vacuum advance mount plate, etc. etc.
My advice is to use one of the small screws on the side of the distributor body that holds the breaker plate, and have a ground wire from there to the engine, like maybe one of the coil mount bolts.
This way there is a good solid ground for the points.
