The 8.75 was used through 74. 72-74 part time 4-wd had 5x5.5 while 2-wd had 5x4.5. 4-wd went to 5x4.5 when it went to full-time 4-wd in 75. Was 74 for the new Ramcharger.
/6 trucks came with 3.91 gears. A lot of trucks had sure grips.
There is good demand for the truck 8.75 as they fit through 93. Housing and axles bring 250.00