1975 Swinger slant 6 Rallye wheels from Coker

Some one will correct me if I'm wrong, but if recall, all Dusters went to the Big Bolt pattern in 1973 when they also went to the single puck disc brake and bigger ball joints.
Nope. Base strippo model slanty cars also came with SBP and 4 wheel drums with either 9" or 10" drums up front thru i believe 1975, and possibly 1976 but I have not seen one as new as 1976.

The real gem though is if you find one of these SBP 73-75s in the junkyard and it has the 10" finned drums on the front, as it has the big ball joint UCAs on it. I would know. I got my BBJ UCAs off a 75 valiant with 10" finned drums and SBP wheels. If you find a 73-76 10" finned drum A body in the junkyard Even if you dont need the UCAs they are still worth wrenching off to sell if they are in good shape,

If his 75 has power disc brakes it's got the larger diameter bolt pattern.