+1. If it's a run-of-the-mill Shimano 7-speed hub, I'd put a fair amount of money on this conversion working. (Pictures always help.)

One caveat is that very early Freehub bodies had a different attachment than the later ones, not sure if Shimano had worked that out of their system before introducing 7-speed. Also, don't try to use a Dura-Ace Freehub body, as they were often DA-specific and not compatible.

http://sheldonbrown.com/k7.html

I've read that some of Shimano's cheapest rear hubs also used an incompatible attachment method but I can't think of the model number -- hopefully Bill Kapaun chimes in on that.

- Scott