Tapered hole in the spindle is too large. I'll have to get bigger ball joints, and from what I hear, Mustang IIs and Dodges have 7* tapers while GMs have 10* tapers, so it might be a good thing to go ahead and switch now.
Greased the bearings and installed them and the seal. Put the nut and washer on it and did a final grind on the caliper bracket. Put it all together and found I have 1/4" play. The outer bearing doesn't seat all the way down. The distance between the bearings is different between the MII and the 5.0. It looks like I'll have to have the spindle turned down a bit after all. Ugh.
So I gave up and tried getting a rear hub off the Jaggernaut so I could put longer studs in. It hasn't moved in a couple of years, so the hub was rusted up.
Hot outside. Decided air conditioning was a good thing.