bad luck with both my squares at the time!! burning up HEI module.. WHY?

[NASTY-LSX]

been working out of town since last year. No love for the 87 1500 or the 85 2500. I've been coming back on the weekends from out of town. a couple week ago i took my 87 out and it just died on me.. still not running. Thats another story..

Took my 85 2500 5.7 out last week to get my wife some dirt. It just stopped while driving. Got a tow truck got it home and there was no spark. Changed out my cap rotor and coil.. Still nothing. Bought a new spark module and it worked fine. Ran 10 times better. 4 miles from home going to get dirt driving on freeway it started popping real bad like the spark plug wires were crossed even at low RPM, then it just died. Got it towed home Same exact thing, the module went out. Got a good 1 from my friend and it burned up 12 miles later..

What could cause this?? My truck ran like a champ.. Well it did lol.. never had problems or hot rod the hell out of it..

Any ideas??