I'm fighting an overheating 289 in my '66 fastback. In order to eliminate the possibility, I want to check the mechanical and vaccuum advance in my distributor. It's stock, as is the engine. I've installed a timing tape, and can see that both mechanical and vaccuum advance seems to "work", but are there specs for each? The shop manual wasn't much help, just talked about putting the distributor in a test machine. Thanks.