I don't know if yours is the same as my '66, but I had a heck of a time finding one that fit. The computers all call for something that's too small. One was closer, but it wasn't deep enough and wouldn't go on due to the spindle making contact with it. I don't know if it's because of mine being a Hemi car or what. I had the same problem with front brake shoes (none of the computers show it as having 11"x3" shoes since the Hemi was new in '66). I finally had an older Napa guy measure my dust cap (the younger people weren't as successful in their measuring) and he ordered me part number BK 730-2412 and it worked. He actually breaks out the old books and finds stuff that way. It's a little tight, and not quite right, but it stays on - unlike the ones that weren't even close. Best thing would probably be to find an old one off a parts/junk car, though.