I have a 454, with a rough comp cam, and a holley 750. I had the carb rebuilt and it was running and idling great. Seems since the timing was reset if the engine is cold it will not idle after a minute of running. Then I'll set the idle up to stop the stalling but once hot is runs too high and I turn it down and the cycle starts over again? It is not the linkage as I just replaced it all and disconnected and I have the same results. Idea??