need help with brake drum I.D

Kuda, I am buying parts for Tylers rearend because that 8.75 came out of a Coronet. I know that because I personally swapped it into his car from the Coronet. What mine came out of I have no idea. I bought it 14 years ago and took it to Moser and dropped it off and told them to cut it down to fit under an a body. I have no idea what it came out of. I don't know if Moser cut the axles, replaced the axles or maybe made the axles and drilled a set of drums for it. I thought that over the past 14 years I had replaced the drums and shoes on it. If so, I know I didn't get them from Moser. The 2603 drum Bill is talking about specs out close to what I have. I didn't put a dial on it but with a quick ruler, the center hole is approx. 2.5 " where it goes over the axle. The width on it laying down with the ruler on the floor to the top of the center hole of the drum is almost 3". Inside of the drum side to side is 10". I know Ford and Mopar has the same bolt pattern but I hope they are not Ford drums. I am going to order one of those 2603DGS drums and see if it works. worst case , I will find me a set of a body axles and stick in it. I know it is an 8.75 rearend with a 489 case.3:23 gears............................I think. at this point, I don't know anything.