Richard, one quick note based on painful experience.  If you change the distributor pay attention to the term "tall deck".  A 427 Chevy automobile distributor is shorter than a 427 "tall deck" truck engine distributor.  When you put the automotive distributor in a tall deck engine it works. The things runs like it never has ... for about a quarter mile down the road when you realize there is no oil pressure because it does not drive the oil pump.  You discover this just about the time the engine stops permanently.

Been there, done that, will never do THAT again