I appreciate your help with vacuum signal on timing. I am running a Quadrajet and I am coming out of the lower small port on the drivers side of carb. I am not sure if that is full time vacuum signal or not?? It has been a little cooooool up here lately to get out there and fire up engine. From what you are telling me I should be on ports above throttle plate which is my understanding is ported vacuum. Bottom line you do not want vacuum to distributor at idle. Problem that I have been having is fast rise in engine temperature at idle. I am running mechanical fan with shroud and electric fan in front of radiator. If vacuum signal was pulling advance on distributor would that cause high engine temperature at idle???????? Thanks for your help.