Let me stick my big nose in here:
John you can turn the shaft down just enough to square it, and make a larger bastard O.D. sleeve, an jeff can make a oversize bore, home made "T" driver to fit the bastard sleeve.
The ball bushing is in a larger counter bore of the home made "T" driver for the driveshaft end.
Personally I would just get a good used hydro and not go to the trouble of R&R of the hydro.
After you buy seals/ gasket you are going to have 1/2 the price or more of the good used hydro price.
The hydro shaft is hardened and I'm betting only case hardened, your gonna loose that.
OR:
you can go undersize on the shaft and Jeff can make you a undersize bore, home made "T" driver to fit it.
But it's your call.
now I'll be quiet.
