A QUICK QUESTION ABOUT MANIFOLD VACUUM

No dial back timing light. I can lean out the mixture with the a/f screws to get into the 13's.

I just found it strange that the mv is perfectly stable at idle, and gets a little erratic in the fast idle zone. I might try the vac gauge on the manifold fitting instead of the car base and see if that makes a difference.

I was just concerned that it may be a vacuum leak........I tried a propane torch around the carb base and intake with no change in rpm.
I'm with the others ... in that it's on the edge of mech advancement during the vac instability