I believe that the hyperglide uses the small cog as the lockring, and so regular casette lockrings on conversion kits will not work. the cog should fit, though they are incompatible the other way around (hyperglide on a modern casette). depending on what the axle has for spacers, you might not have to re-dish. maybe consider respacing the frame?(only if it is steel) if it is quick release than you will need to cut the axle or replace it. I think converting those wheels will be more trouble than they are worth. Since you are buying new wheels, I suggest you reconsider. those wheels will be a major buttpain most likely.