Timing Dance ! Vacume Advance ?

Pilots,
As was noted, initial and total timing should be checked with the vacuum can unplugged and the line to the carb capped. Thsi is to eliminate any variation the vacuum advance might be adding. If you do this and it still moves, it could be seomthing mechanical but I wouldn't worry about it. Simply keep an eye on it. If it gets worse you can look into it. There is an adjustment on teh vacuum can on the dsitributor. Take an 11/32 allen wrench and go straight into the nipple where the vacuum line plugs on. The wrench will go in and seat in a screw inside there. By turning that screw counterclockwise, you add preload to the advance and slow it's response. This does not limit or change the amount of degrees it adds, just raises the level of vacuum required to move it. If I had to guess I'd say your stumble is the advancetrying to come in too early when the vacuum signal is changing with the throttle at part throttle driving.

T67 - I'm pretty sure there are a lot of guys that know how a vacuum advance works, and want it. Perhaps if you want to convince someone to try it, explain why without yelling (CAPS). Saying don't think just do is just stupid... we're here to learn. Not take commands.