That's the hard way to do it. Just slap the 2WD flange on the 4WD differential. 5 minutes tops.
How hard that? ^^ Never looked at 4x4 so...
Where the 2x4 b2600's lsd rears?
I don't know about the 2x4's. I have an '89 2600I 4x4 and when I'm in 4wd low, the rear axle clicks like it has lockers in it when I'm in a tight slow turn.
My manual also reads the 2600I axle is a 4.3 gear ratio. It does mount with the leaf springs on top of the axle.
There was never any sort of LSD in the B's ... unless you count other countries.