:confused: engine is 355, w/comp 274-230deg@.50, its only got about 5000 mi on it the carb is a holly 670 w/elec choke. somtimes it will suddenly run like its on 4 cylanders (really rough) and ill take it up to 3000rpm or so, and it will smooth out completley, and then run fine. it will start this when i start it up, or somtimes when im idling at a stop light. feels like maybe valve timing or carb problem. i am stunned because i have checked plugs, look they good, and no leaks i know of anywhere. any advice would be helpful

Maybe the plugs are the wrong heat range..?