I hope some of you can help. I have a 1941 Oliver 80 row crop, that has been changed to 38" rear rubber, on Super 88 rims with cast centers. The hub that was used to mount them to the axle is cast with number BC704A. I can't find this part number in my 1941 or 1947 80 parts book, or in a 70 parts book. B704A is a tapered clamp for 70 cast center, and C704A is for an 80, but the BC704A fits on the 80 splined axle with a 9 bolt pattern to bolt on either a pressed steel or cast center. Can anyone help me identify what this is off of, or does anyone have a set for sale? I have another 80 with 40" original rubber, which is on its last leg, and need to replace it. Thanks for any help.