66 dart rear end swap

Back in the day, I had a friend with a 66 Dart; 273 four barrel 235 horse; four speed; 7 1/4 posi. He bought it used and beat that car for two years before the rearend let loose. 4,000 rpm and dump the clutch; hundreds of times. He put a rearend in it out of a 63 Plymouth Belvedere. Bolted it right in. Kinda wide but today you could find offset rims all over. Forget that Dana; you have to cut and replace both ends and buy axles. Run the 7 1/4 til it gets sloppy then switch in a 8 1/4. Carry one spare with an adapter. Run a 904 and you can use the same driveshaft and trans mounts; nothing changes back there. 727 requires cutting the trans hump on both sides near the front of the bell. Plus it interferes with the floor brace above the crossmember. Some 727s have a rib on the tailshaft housing that hits it. My 66 Dart came with a 360 and 727 jammed up in it. I put in a 904 and am running the 7 1/4 until it breaks. I already had a sbp 8 3/4 so that will go in at that time unless I sell it then I'll go 8.8 narrow one side.