LK,
Max 4/0, as with all 2" LBs?
I think you'd be better off to follow gserve's instruction, and look in the inside of the LB.
From the OZ/Gedney catalog:
LB-200A = Max 3 #4/0 AWG, (aluminum for rigid)
LB-67 = Max 3 #1/0 AWG, (a Form 7 LB)

I regularly see the use of 2" Appleton LB's (aluminum) Max 2/0 with 3/0 wire on 200 Amp circuits...S

[This message has been edited by electure (edited 01-18-2004).]