Just got the 67 GTO back from the shop after an engine rebuild and transmission swap. The car runs really well but I'd like to get my vacuum advance into the mix. The engine is a 461 with a HR cam, Eheads and about 10.4 compression. The car only sees street use so I would like to gain the efficiency of the extra timing advance under partial load and idle. I dusted off my timing light and with the vacuum pot disconnected the initial advance is 23 degrees. I didn't dial it back far enough or rev it far enough to see what the total advance was but it was at least another 12 degrees if not more. Is there any possible way the vacuum pot can be used without introducing pinging under light load?