My sons Dart runs 11.40's at about 3600 lbs and has had the same 8-3/4 in it since 1997. My 63 runs 11.50's and has had it's 8-3/4 in it for 2 years since I got it on the road. Both are stock rears with stock axles but I did put a Detroit Locke center section in mine. And both are auto's with Dynamic 9.5 converter's. It should hold up fine in a low 12 high 11 car and even better with after market axle's. Ron