1971-73 Mustang Alternator - D7AF-JA  40A  Housing with 71-73 plugs.  This alternator has a 1977 housing nut is made for 71-73 Mustangs.  Someone bought this as a rebuilt someone along the lines for their 71-73 Mustang (came out of a 1972 Mustang with a 302 engine).  If you just need an alternator to rebuild, then this is for you!!