As stated above, the pinion support on a stock 9" is not to strong. I have seen many pinions spit out the front of 9" center sections at the track. Of coarse you can buy the new beefed up center with 12 bolts , bolt through bearing cap retainers, back brace the housing, weld on chrome moly housing tubes, or just put in a stock dana to achieve the same results. My Dana has been under my Barracuda for 40 years with thousands of runs , Still running the original bearings. and brakes.