I can tell you from experience with that blower if there is any? then go rich first. 750 carb, 7 lbs. of boost and stock jets sounds lean to me. with the same boost, same carb. it took me 90 jets in the front and no jets in the rear to get through the 1/4 mi. (without burning a hole in a piston or blowing a head gasket) and that was shifting at 5500 rpm.