If you are still running the stock 7.5 diff in your Regal(all 307 Regals used the 7.5) and the 3rd gen diff is from a 82-89 than you can. 1990 and newer F-body has different axle splines and they wont work. 82-84 F-body was 7.5 and 85 and newer was 7 5/8" but are interchangable. Make sure you use the ring and pinion that came with the diff. One carrier take 3.08 and numerically lower gears and the other uses the higher gears. If the diff came out of a 3rd gen with the 9-bolt cover than it difinetly WONT work.
Eric Fisher
