manifold vaccum for vaccum advance ?'s

Take a step back for a minute and relax. 14 to 16 initial should not be too much. The suggestions are being made to try and help you eliminate the problem.

You say your hearing a popping noise in the exhaust. Have you checked for vacuum leaks? How about an exhaust leak? Are you running headers?

I agree with an earlier post as far as not changing more than one thing at a time. When tuning it should be timing first and then carb.