My dad had a 8 3/4 in his duster back in the mid 90's. (440 ran 7.30's in the 1/8th has been in the 6.80's more recent years) Would break a ring and pinion every year. Finally put a Dana in it in the late 90's and hasn't broke anything in the rear since... He did build a duster for my sister in 2011 with a 360 run's 11.80's with the 8 3/4 and hasn't had a problem with it...Keep the build simple and low torque and you'll be fine. Increase torque and power, you'll find the weak link.