Lower Control Arms - A vs B

If you look closely at the lower pivot shaft, you will see the difference. Although I don't have a B body one here, I'll explain the difference...

The B body shaft has a longer machined flat before it starts to taper than the A body one does. I don't know off hand if the shaft is a different diameter or not, or whether you could replace the B body shaft with an A body one, but I know the shaft is machined different for sure. Maybe somebody else could chime in with an actual measurement of each shaft. That's all I can add, Geof