Hy guys, those wheels sounded rare/unusual to me also, so I did a little research. 1960 40 series, had two different 18" wheels, one 18"x5.0" p/n 2364442, side ring 3707074, locking ring 3682062, and one 18"x5.5" p/n 5769144, side ring 5769145, hope that helps.
