ok, I have working on this issue, the 3 circut carbs are designed to run on a trans brake only leaving flat on the floor(they don't tell you this in the specs) but if you try to leave part throttle(like we were doing) it runs like crap. the carbs have a extra circut for dumping fuel assuming you are already past the accel pump shot, so after talking to holley tech modifyed my 3 circut and made it a 2 circut and works great...Rob