the light trucks 58-61 were called Apache, simply a marketing gimmick designating trucks up to 9000# gvw, the medium duty trucks were Viking, the heavy duty, Spartan ... in 62 they switched to the "letter" series designations
"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir "When we tug a single thing on an old truck, we find it falls off" ~ me Some TF series details & TF heater pics