I purchased a used HEI distributor and have little knowledge of how they work. I am curious about how the centrifugal weights work. It looks like the two sets of pins that hold the weights and springs rotate a little independently of one another. My question is how freely should this pivot point rotate back and forth? Because on mine it is very difficult to twist them it if at all. It may be that I need to take it apart and clean it and lube it?

They should be very clean and should move with little resistance except for the pressure the springs produce. As the distributor speeds up the centrifical force increases the weights begin to rotate outward on the pins and push the other pins with them and this in turn advances the timing.

So get some LUBE!!! :D