The original poster said:
Selling the rearend out of Modoba. Gears look good, sure-grip works great, axles splines showing some wear. I'm upgrading to a 8.75 with disc brakes. Brakes are in very good condition, they have about 21,000 miles on them. 250 for the housing 300 complete with brakes. I'm in Akron, Ohio. I think the drums are stock 10" size. but will have to check.
There is no mention of if his original differential is 7¼” or 8¼” – but everyone is assuming it is an 8¼”.
Not very many limited slips were made for any 7¼” either from Chrysler or aftermarket – so again, I would assume it to be an 8¼” because it has a limited slip (he does mention sure-grip).
On a different note, almost all FMJ’s came with 10” rear brakes.
Only Police, Taxi and “some” towing package cars (not very many) came with 11” drum brakes. I would say (but no numbers to back this up) that only about 1% of all FMJ vehicles came with 11” drums, and that number may be on the high side - Maybe closer to ½ of 1%.
11” drum brakes will fit on either differential (and even the 8¾” that Original Poster is planning on using - but he said disk's) – but it looks really out of balance when you look at a 7¼” with 11”s (big brakes . . . tiny differential).
The factory did not make any 7¼” with 11” brakes for, I think, the factory was thinking if you need the bigger brakes, you also need the bigger gears (I shrug).
The only thing not answered, is if his differential is a 7¼” or a 8¼” – and it sounds like we won’t find out until spring.
BudW