8.25 vs. 8.75?

Yeah it's a 727 from TCI. The casting on the 8 3/4 is 489. I was told the 8 1/4 that is in it has 3.73 gears. It runs good now with no noise, except the driveshaft I think is too short now. There is a little sound from it at the tranny tail shaft.Thanks for the feedback!