GM Heritage specs call for 4 degrees btdc at 550 rpm, make sure the dwell is correct first at 28-32 degrees at idle, then adjust the timing. If you advance the timing too far, the idle speed will be too high. I have mine at 6 degrees and things work pretty well. When you disconnected the vacuum line between the diaphragm and the distributor, did you plug the end of the line when test driving?
Last edited by 78buckshot; 11/05/2024 6:34 PM.
