Sometime back I had a couple of problems, pinging and paint not laying down.
For the ping, I finally just yanked the 41288 dist in the 74 1/2 after trying the ported vacuum and premium gas, both of which were improvements, not cures. I replaced it with a mystery distributor that isn't listed, because the vac adv. looked right. It worked!
As for the paint problem I substitued paper towels for my shop rags to apply the de-greaser. The paint doesn't move away from some places now, so y'all must be right about my "clean" rags having some contaminant.