318 stalls at 45 mph

[Brian]

I have a 1972 318 mostly stock but with Edelbrock Performer manifold and Edelbrock 600 carb. I recently put in a Pertronix coil and electronic ignition system. Since then, I'm assuming that it is related but maybe not, the car sputters and stalls every time at 45 mph. When in neutral or park, it does not stall ever, even when reving the engine, only stalls when in gear. Any ideas on how to fix this?

 

[69 Runner]

First thing I'd do is put things back the way they were and see if it stalls. Or, since it will be a little involved in taking the electronic out, I'd at least swap the coil to see what happens.....then maybe the electronic if it still does it.