If you have a NAPA in your area, I would go there first. They've came up with all kinds of stuff for my truck. If all else fails, could you grind off a little of the shoulder on the one you found at your local store so that the drum would clear?

http://s1202.photobucket.com/albums/bb364/Dirty_Gurty/

1949 Chevy 3800 with dual wheels