sorry I should have updated my post earlier. I found that after some research that they are the same...just different. Several of the sites selling drums classify them as the same part number but with an "A", "B" or "C" behind them. While the 58 and 61 drums are the same diameter and depth (external rim to rear), the lining cut and face recesses are where the differences are. In the case of the 61 drum the cut is 2.5 inches where the 58 drums are 2.34 (58 has a thicker shoulder). Also, the face (hub mating area) on the 58 is higher meaning when the drum "seats" in the rear your still about a 1/16th of an inch from the face seating on the hub as well as the shoe depth throws you off. So I bit the bullet and bought new drums...
Bill