I bought a 750 annular mighty demon(general competition) a little over a yr. Since then (351 windsor) ported 1970 heads with large vlvs. , scavenge collectors with a nice 2.5'' exhaust. The cam is small (.500 and 218 @ .050) stealth intake matched to the head, not the gsk. Before all these changes (motor already with cam and intake) the carb seemed to be better than what was on the car. After the porting and 2.5 exhaust, that demon was a demon ( severe surging, would not idle).Called BG tech line(what an _______ I got hooked up with)
and asked for the simple jett sizing. The carb was 2 sizes smaller than BG said.I'm no expert but I knew it was going to take more than 2 sizes to cure a severe lean condition.Went 7 sizes larger than what the carb came with( found a chevy site where they dyno tuned the same carb)! Mine is a mild street build. Went to a .060'' IAB (from .070'').This helped the idle and part throttle cruise. Drilled the pump shooter from .031 to .040.That also has helped when you step on the gas, but still can go bigger. Would I Buy another...probably not. This carb was a new ebay purchase. When recieved, I took it apart(curious with the new toy) and on the main body where the metering block goes, that machined surface when machined had about an .080'' step! Something in the cnc program (glitch) went ''haywire''. Sent it back and got another.The booster(banjo fittings) were not on the same plane, mine are now thanks to a mill and a tender touch.I'm still playing with it. Will get an A/F meter to continue for the fine tune along with a trip to Maryland International Raceway.Gonna feel good to run that stang through the gear box!