The cam should be lubed which should help prevent this:
I found the following on line:
"Mallory Distributor Lube (Cam Lube Grease), .25oz, 26015 is the PROPER high temp grease to use on the distributor cam lobes, where the rubbing block of the points rubs against. This location is often dry, resulting in "squeaky" points operation.
This high temperature grease won't fly out onto your points like Vaseline, or other greases! STICKY to stay on the distributor shaft and centrifugal advance mechanism. This is also EXCELLENT for the needle bearings for your transmission input shaft, it's usually inside the engine's gland nut.
You should put some of this on the point lobe every 3k miles. This is also GREAT for input shaft and throwout bearings (inside the gland nut or flywheel), since it won't get hot and then fly out onto your clutch! Also used for generator or alternator bearings. This is a must for your garage. "