Turning a 74 into a 72

The sure grip unit looks like an auburn. The way to tell is whether the case has bolts going through the one side of the differential to the other, auburns do not have the bolts.

Your build is going great. I knew someone that transplanted a front clip like you did, only on a 73 dart sport, it looked fine !

My guess is a 73 swinger would have been easier, the rear panel is probably darn near the same as the 72 - I think. But no matter, its coming along terrific ! Keep it up !