Ignition experts needed

I'll start from the beginning. Bought my 71 340 with an Accel Street Billet distrubutor already installed. Ballast resisitor bypassed correctly. With a Pertronix coil. Car ran great since September, but a week ago I started having an issue.'
The thing would be purring right along and just die. Running in gear and the tach would drop to zero. The tach wouldn't die if it was a fuel issue. Thought it was a coil, so I decided to instal an Accel 300+ Multi Strike ignition. Used this before and loved the start up and throttle response. Out with the old, in with the new. Wired perfectly. New plugs and wires too.
So....after a small dilemma, fire her up today and wow! No cold blooded start...real snappy throttle response. Get her warmed up and off I go.
3 blocks down the street, it dies. SAME way as before.......tach drops to nothing and dies. Just like you shut the key off.
Jump out, open the hood, look for....something wrong. Jump back in and bang...starts right up. Close the hood and it dies. No restart. I waited 2 or 3 minutes and she starts right up.
I limped home those 3 blocks with several stalls and waits to restart.
HAS to be electrical due to the tach dying when the engine dies, but what?
Is there some relay or regulator on these Mopars that could be the culprit?
Could it be the magnetic pick up in the distrib?

Sorry this is long winded but I'm getting desperate. I have no access to any info other than you guys, and I hope someone can point me in the right direction.