Camper Specials (Camper Customs in GMC) were mostly 3/4 ton trucks. Depending on year and equipment, they could be both coil or leaf spring (I've seen them both ways), though most were leaf spring. The leaf spring models were built using the GMC chassis, and came in 2 lengths. The regular C20 Camper Special used the standard 127" wheelbase, and usually (again, I've seen them both ways) used a Spicer 70 rear diff. The few coil spring trucks I've sen had the Eaton. The Longhorn, which had a 8.5' bed, used the 1 ton chassis, which was leaf spring on both Chevy and GMC, and had a 133" wheelbase. The Longhorn, also avalable without the Camper package, didn't come out until '68. All Longhorns were Fleetsides, and were availabe as a C20 or C30. Most Camper Specials were built for slide in style campers, however, some were built for use with chassis mount campers as well. I have seen both wheelbases that had chassis mount campers with the dual rear wheel option. Dual rears was optional on 3/4 tons at least until '71/'72.
Chassis-Cab Camper Specials were not available with the Cheyenne/Cheyenne Super side trim. It is not uncommon to see a Camper Special with a 396/TH400 combo, though the 350/TH400 combo wasn't uncommon in the either. I've never seen one with a manual trans or 4x4. The dual tanks were not factory, but a dealer install option. Most of them I've seen with the extra feul capacity option actually have 3 tanks, the factory tank in the cab, plus 2 saddle tanks on each side of the frame. IIRC, the saddle tanks were 20-25 gallon capacity.
I grew up around these trucks. My Grandpa had a '69 Camper Special he bought new, it was optioned with the 396/TH400, and always had a camper on it when he was alive. My Uncle Louis (Mom's side) still has the truck. My Dad also had a C20, not a Camper Special, 350/TH400, 4.56 gears and the Cheyenne package. My Uncle Fat Rat (Dad's side) bought it from us in '78, and had it for a long time. It belongs to a body man in GA now, as the Rat traded it for a '64 Chevelle SS. My other Grandpa also had a '70, his was a C10, and the fab shop my Dad and Grandpa worked for had a '71 C20 Longhorn. I came close to buying one myself, a '72 GMC Camper Custom, but passed on it because I really wanted a Task Force truck.
