8 1/4 vs. 8 3/4

FWIW: In 1982 we built A 13:1 69 340 Dart. This thing spun to 7800RPM on a regular basis & saw a lot of street action. We assembled a 5:10 geared 8-1/4. It lasted all of 2 weeks. We replaced it with a 4:88 geared 8-3/4. That rearend was still in the car when I sold it.