Im not sure what it is youre asking. I purchased the Reyco/Granning rear air suspension kit from Stengel Brothers brand new. It shipped on a pallet direct from Reyco/Granning to me and i installed it. Reyco/Granning makes a kit for the F series but i dont know anything about the F series pickups or what years they cover.
I installed the kit about 5 years ago but my plan was to remove the rear air suspension and install custom rear leaf springs to raise the rear to match the front ride height since it now sits higher in the front with the 4x4 axle underneath.
Why would you think you need a rear axle?