Air bleeds operate in inverse proportions to jets- - - - -smaller is "richer". Dad used to adjust main jet mixture on his alcohol/peroxide fueled round track car by changing main jet air bleeds, since the jets had been drilled out so far they tried to break off when they were tightened firmly. He was using a big 2-barrel Zenith carb for a Mack truck on a 300+ cubic inch flathead V8, and flowing more air than his competitors with 3 Stromberg 97's.
I have a sneaky suspicion you're over-carbureted. Have you considered using a Quadrajet for a 500 cubic inch Cadillac engine? It flows over 800 CFM, and the secondary air valve prevents bogging when the throttle plates are dumped wide open. I got 714 HP at 6500 RPM from a 460 cubic inch MOPAR 440 truck pull engine, running one of those carb- - - - - - real dyno numbers, not pipe dreams conjured up while bench racing!
Jerry
