Now since vacuum advance is the only thing that affects rotor phasing, I can also pull the distributor from the engine, throw on a different cap with a hole drilled by the number one cap terminal, apply my mity vac to the vacuum advance and then turn the distributor by hand to watch how far off it is from the cap terminal too correct?
This seems easier then trying to be over the top of my engine while it's revved up to 2500 trying to look down a little hole with the timing light.