Mike,
Have you seen the FWW article where an Oliver 12" jointer was refitted with a Shelix head? http://www.finewoodworking.com/item/...orking-eletter
I have an old 15" jointer that I think is a WW Carey but a bit older than yours that I will clean up. It has a square block cutterhead and would be a good candidate for a ball bearing refit in conjunction with a newer cutter.
Yours looks to be in great shape, have fun.