how strong is the 8 3/4 #741 case?

A friend ran a 741 case in a 71 Swinger with a mild 440, high stall converter, and 10 inch slicks. After about 7 seasons, a tooth broke off the ring gear, but this was caused by the center section having sat without rotating for several years prior to him buying it from a salvage yard. Over the years of sitting, the oil residue had all drained away from the top.of the ring gear, and it was visibly pitted pretty badly when he purchased it. He simply cleaned it up and sent it. No shame in that spot coming back to bite him after 7 seasons at the track.