I tend to agree that there is nothing wrong with ball bearings, but am a little concerned about 70-75 mph interstate driving--very common when we drive to car and truck events some distance from home. If this whole thing doesn't pan out, I'll just go back to ball bearings.
However, this is what I've found out so far. Both are roller bearing and race part numbers.
Classic Performance Products kit at $119:
Seal: National 6064
Inner: MBS 909052R
Outer: MBS 909067R
Chevies of the '40s at $235:
(Why so much, I don't know.)
Seal: 3656536
Inner: 909052R
Outer: 909001R
Tech at CPP did say they have experienced some problems with the seal seating and had to use a hammer and punch at 12-3-6-9 to get it to seat. Sounds kinda' hokey.
Well, off to check with local bearing supplier. I'll report back.
