wydtrac.....My 1960 Master Parts Catalog lists the number as 531959. I checked the 1972 Catalog and it lists the same number for 1961-62. Interesting that the bar is described as 11/16" and the hole as 5/8". Tight fit, so grease them up good! The catalogs also list Heavy Duty Police bars at 3/4" with 11/16" hole. Good idea to take your bracket off the frame and take it with you to NAPA to be sure.......John