I'd be a concerned about the clearance between the blades and stays. A lot of the older middleweights didn't have a lot of clearance. It may be tighter than most peole think. You may have to keep a close eye on wheel true.

You'll lose about 1/2" in BB clearance, which I don't think will be as big an issue. Dropout spacing may or may not be issue, depending on what it was orignally designed for.