Have you made sure that the adjuster screw is all the way back in? Plus, the parking brake might be a little tight, too. Try adjusting it back as well. As far as the drums go, it had nothing to do with them being old, it was the guy who attempted to turn them being incopetent. If it dug grooves in them, either the bits were dull, they tried to take too much out in one pass (trying to get it done in a hurry), or the feed rate was too high (again, in to much of a hurry), or most likely a combination of the those. I would almost suspect that they either gave you the wrong part (unlikely, the drums are the same '51-'70), or more likely, el cheapo overseas cast drums. We run into that one regularly when the customer wants to do the job as cheap as possible. Have the drums mic'd. They should come out to a nominal size of 10.090" to 11".
