1965-1966 XLH had a 12v coil mounted on a two holed boss under the seat casting on the right side of the bike with an angled plate (31727-65) holding the coil on.
1970-1972 XLH, XLCH coil moved on top front of the rear fender using a lengthened seat post retaining bracket (51526-52A).
The -52A bracket was also sold as replacement for 1965-1969 XLH models.