Spline?

From 73 on up all 10" drum brake cars and disk brake cars were 5 on 4.5" weather they had a 7 1/4 or an 8 1/4. No you cannot just swap axles from a big bolt pattern 7 1/4 to a small bolt pattern 7 1/4. the bearings are totally different and not interchangeable. If you want big bolt pattern in the rear your best bet money wise is to find a big bolt pattern 8 1/4 in a yard. Look for V8 A-bodies. The drive shaft should be shortened a bit going from a 7 1/4 to an 8 1/4.