I have 12 initial 38 total without the vacuum advance hooked up. I used my mitivac on the vacuum advance. I seem to be getting around 25 degrees with 15 vacuum. With the vacuum line hooked up to ported vacuum I end up with about 50 degrees timing when I speed the motor up.. I think this is causing my surging at cruising speed. My vacuum advace appears to be non adjustable through the hose barb. How do I limit the vacuum advance and how much do I want. It does not have a stock camshaft. Its a new dist. with light springs so the mechanical comes in pretty quick.

Kenny  Onalaska, Texas