[mud.man.rj]

I would pickup a carb with ported vacumn and run both this will give you your best ecomomy, but if not wanting to change carb then eliminate vac advance and just run a bit lighter spring on mech advance to get between the best of both. The vacumn doesn't work or induce advance until you are under part throttle operation and helps a bit to stop initial bog or lag off of bottom end only then mechanical advance takes over. I run a mechanical adv only with big cams and change springs till I get it where I want it.