Stumped by a timing problem

[MAC71]

Originally Posted by tranz am

I think that what you are experiencing is an extremely lean condition in your carburator. The vacuum advance is just making it more noticable. At 2200 rpms you are not fully into your main circuit. I know you said that you richened up the carb but just changing jets does not change your idle circuit which is probably where this is taking place. Try adusting that by swaping out the air bleeds. Big blocks like about 35° total initial & mechanical and 8-12° vacume advance on manifold vacume.

The carb is just a 1850 so no screw in air bleeds or IFR's. I did try a eddelbrock and no difference.
I just re checked my timing.
12 initial
35 full no vacuum advance
and using a vacuum pump I discovered that the vacuum advance adds 12 degrees, but using my dial back light full with vacuum advance looks to be around 44 degrees. I checked initial using a normal light and it matches the other light at 12 initial.