Thanks Mallard. I may just throw another carb on it just for kicks & giggles to see how the car responds. I'm convinced it has something to do with timing. I think I'll try slightly stiffer mechanical advance springs in my HEI distributor, to see if maybe the advance is coming on too soon causing an extra lean idle mixture??? I was also thinking about hooking the vac. can to ported vacuum to see how the car responds. Ported vs manifold vacuum seems to be an ongoing debate in many forums. Feel free to give me your opinion.