Are '73+ 9"drums, same as earlier years?

I think your answer is YES, and that agrees w/ what hemi71x states. People here have reported some 1973 cars w/ 9" drum brakes, and all of those had the "small bolt pattern" of 62-72 cars. Thus, it should be the same spindle as on 67-72 9" drum cars.

One question is why Wilwood specs from 1967, since I thought the same 9" spindle & drums goes back to 1962 (or 1960?). ScareBird also has a disk conversion for 9" drums so see what years they spec.