To the best of my knowledge, the original Centerline Tool Co. Autodrags came in 8 1/2 x15 , with either 3 5/16 or 4 7/8 backspace. The 3 5/16 worked best on full-open wheelwells, not so well, (if at all!) on cars with smaller ww openings. I'm currently using a 15x8 1/2, 4 7/8 bs sbp autodrag on a 62 savoy, that has been double drilled to 4 1/2. It needs about .300" spacer to get the tire away from the spring. The sbp autodrags used a smaller than normal center hole, to give more meat around the inside of the small bolt pattern.
