The ingredients to his early tone is a culmination of low output pickups, into an overdrive pedal, into a cranked Marshall. I wouldn't exactly call that "nuclear distortion pedals". In fact, quite the opposite. Just a strat, plugged into a boosted Marshall, is pretty straight forward. He likes his string action high, and the scalloped fretboard requires a consistent even and light touch. It is that gear and his vibrato technique that carries the notes. Again, the amps are cranked maxed out. I don't think anyone else can play with that combination of equipment, including the light strings,, and sound even close as good. He is a guitar god for a reason.
For a better example of his early heavy rhythm tone, check out his Marching Out album. Songs Disciples of Hell or I am a Viking.