I have two different carburetors. Both build for my specs by Cliff ruggle and Quadrajet Power. Both run great, no hesitation and with 96 octane, can run great. So don't think it is a lean condition. If I bump the octane up by using 110 racing fuel, if I get it around 96 I'm fine. I can not use some of the octane booster like Klotz Octane Booster. It does not seem to help. But 2.5 - 3 gal of 110 to a tank does.