I thought converting a 14BSF from 6 to 8 lugs, or vice versa, just involved swapping axle shafts... 
Or are the new 6 lug and older 8 lug different widths?
I ask because I'd like to go with a 6 lug 14BSF in the rear of my K5, just for strength when I occasionally pull a trailer.

Or are the new 6 lug and older 8 lug different widths?
I ask because I'd like to go with a 6 lug 14BSF in the rear of my K5, just for strength when I occasionally pull a trailer.