hotrodder 858

19865 mustang stock 289 has dura spark 2 dist. runs great with no vacuum advance, hook up vacuum advance it dies just past idle. Tried different dist and modlues.

Mostang66

I've been waiting to see if someone would respond to your problem. I have a Shelby dual point (converted to Pertronix), which is mechanical advance only. There should be others who have more practical experience with vacuum advance on a 289 to respond. Regardless, you are obviously using ported vacuum (timed), which should be O.K. What do you have the ignition timing set at with the vacuum line disconnected? It sounds like there should be a little less advance when you initially set the ignition timing so that when the throttle plate begins to open and vacuum is introduced, it doesn't slam the ignition too far in the advanced direction.