I have a Holley 650, Excel ingition, mild cam, TH350 tranny. The car idles great and has 20 to 25 lbs. vacuum when idling. As soon as I shift the car into drive it wants to die. Checked vacuum and the modulator is fine. Shifts and drives great but under load at idle it dies. Any suggestions???HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! We went through everything, timing, carb etc. There are no vacuum leaks. The engine was just rebuilt with all new everything. We are at our breaking point with this!!!!!
Any help appreciated.