1970 duster slant six 8.25 rear swap

Talk about overkill, my 70 Dodge Challenger w/ a SL6, auto. (904) originally came with a 7 1/4 rear end. However at 225K miles as a daily driver, I believe the gear set was 2.76. The spider gears decided to go south, with that I was looking for a replacement. A guy I knew was parting out his big block '71 E-body. So for $55.00 I ended up with an 8 3/4, 742 case w/ a 3.23 gear set. 11"x 2 1/2",brakes and finned drums,a single legger. W/ 1 3/4 pinion. Cut and rebalanced driveline. Overkill! Ya think?