Here is some info that I had saved on the older stuff. I am not sure on the new stuff.
Spacing
1-tons feature 40.5" perch spacing - whether C&C or pickup, whether SRW or DRW. 3/4-ton is 42.5" perch spacing.
Width's
SRW 67.5" WMS-WMS
DRW 72" WMS-WMS
C&C 63.5" WMS-WMS
VAN 70" WMS-WMS
GM Dana 60 front (single wheel) ...................69"
GM Dana 60 front (dual rear wheel) ..............77" ; +4" on each side vs single wheel
GM 14 Bolt rear FF (single wheel) ....................67"
GM 14 Bolt rear FF (dual wheel)........................63"
GM 14 Bolt rear SemiF (single wheel) ..............66"
GM Dana 44 Front (single wheel) ..............69"8-lug; 67" 6-lug
GM 10 bolt front (single wheel) ..............69" 8"lug; 67" 6-lug
GM 14 Bolt rear (Van single wheel) ...............70"
GM 10, 12 bolt rear ..................... 65"