OzyDuster74 full rebuild and hemi conversion!!

When we were welding i noticed one of my hand brake lines from the diff melting. Then noticed smoke coming from the brake drums hahah.
The earth was on the right side chassis connector and we were welding on the leftt. The current was going through the diff and cooking everything, the rubber was dripping out of the hand brake line. Not something i thought would even be remotely possible.
Luckily not the diff i am using