[Mike C]

Several things here:

Burnouts on a peg leg axle will tear up the diff in no time. The spiders spin around the center pin at tremendous speed, they were never designed for that and will fail sooner rather than later. Don't do burnouts until you get a limited slip.

Most likely you broke the pinion gear yoke as well. One of the little "nubs" that align the caps underneath the u-bolts likely sheared, but maybe you got lucky. The truck 12 bolt will survive some abuse, just stay away from big tires and clutch dumps or you will continue to break parts. If it ever starts wheel hopping on you, back off immediately or prepare for more internal damage.

10 bolt is a pretty decent axle, actually. The 88 and up with 30 spline axles are stronger than a truck 12 bolt because of the previously mentioned larger pinion diameter. The difference between 8 7/8 ring gear and 8 4/8 ring gear not all that significant. The 12 bolt ring gear bolts are smaller diameter and right hand thread compared to the larger diameter 10 bolts which are left hand thread so run without lock washers. I have built several that survived seasons of 1/4 mile passes in Camaros and Firebird running in the mid 10's. Most of a bolts bad rap is from the early 8.2 found in Camaros, Novas and Chevelles in the 60's and then with the 7.5 in the Vega, late 70's and 80's G-bodies as well as the F-bodies.

The 10 bolt is certainly NOT an upgrade. Cheapest way out if you cannot re-weld yours is to just replace the whole thing.