Just after jetting up my 670 holley on my 390, I was driving it hard to see how it ran, and it ran great, then after coming to a stop, it barely idled anymore. Prior to it going bad, it idled with my msd box at 12 degrees at around 700rpm in park and it would drop to 500 in drive without ever dying. I checked for vacuum leaks, checked inside the dist, blew out the idle air bleeds, I even rebuilt some of the carb, blowing out the metering plates and replacing gaskets. After the rebuild, it ran better but still barely idled. the idle mixture screws don't seem to have an affect, but the carb idles normally if I put the choke on, but then it won't accelerate past Idle. It still cruises and accelerates normally and really good, no smoke from anywhere or any noises. Any Ideas with whats wrong? I figure its with the carb considering rebuilding it helped and it idles with the choke, but I already checked the air bleeds real good.