Earlier this summer, the Fastback's 342" (MSD 6AL box, MSD 8579 Dist, MSD Blaster coil) just clean shut off while idling at a STOP sign; and would not refire until it sat for 15 mins. During diagnosis of the problem, I only found a faulty alternator and replaced it; but also installed a new voltage regulator, MSD magnetic pickup, dist cap, and rotor to cover other potential issues. All has been OK for about 2 months of cruising until this evening. The engine again cut clean off at a very busy red light; and would not refire. My wife and I pushed the car into a nearby MacDonalds (I'm 63 and she is 60!). After it sat for a while, it refired and we started home. A few blocks from home, it cut off again; same thing. I checked the fuel while it wouldn't start and there was plenty of gas in the carb. Now at home, it runs fine; but I don't trust it on the street. Is it possible to use a Duraspark box and Duraspark coil with the MSD dist? If so, I could rig it up to switch to one or the other during a failure in the hope of pinning down the problem. The car has been on the road (actually during summer) for over four years now; and this is the first problem.