My experience with the 8.25/8.375 is when going from a 2.45 gearset to ANYTHING lower, a carrier swap is in order. Not a big deal since not too many of those rears were cursed with 2.45 gears. A trip to your local u-pull-it should fix you up for less than $30

1969 Nova
454/M21/3.31
Mild mid-11 second weekend cruiser

1994 F150 XLT Super Cab 2WD
5.0/4R70W/3.55
(Daily driver)