johnnyboy:
I had a heck of a time with my 3/4 ton balls. lol.... I finally just packed the crap out of them and did the unthinkable, I mixed my greases. This gave me a slightly thiner grease which works really well. It worked for me.
If you don't want to mix your greases as did I (which is quite understandable) just pack tons of grease in there. So much so that it is almost overpacked. This is the key to heathy balls.
I had a guy at the local auto parts look up some roller taper bearings for me that would fit my 62, 3/4 ton. He found some that had good specs. I didn't try them though because method is working fine.
Does anybody have a link for the conversion kits?