Engine dies

1. 1977 Jeep CJ-7 (304 V8)
2. 47,000 miles
3. Stick Shift
4. Strange sounds or smells-None
5. Fluid leaks - none
6. Past repair history Lot’s of UPGRADES

Hello,
I have a Jeep CJ-7 with a 304 motor. It has a lot of upgrades the major ones being fuel injection and MSD wiring. My problem is: It starts and runs great but I can be cruising down the road at 20, 30 or even 50 MPH and the motor just suddenly dies (doesn’t cough or run rough just loses power completely). I put it in neutral turn the key off and then re-crank the motor. It always starts right up and I continue on. Sometimes it won't do it again for an hour and sometimes it does it over and over.

Thank you for any help,
Mike