GMC Six by Sixes were two-and-a-half ton trucks produced by a division of General Motors during World War II. According to GM, between 1941 and 1945 around 525,000 of these vehicles were produced "in different lengths, configurations and body styles including cargo trucks, dump trucks, tankers, bomb transporters and fire engines."
How It's Used
“The courtyard echoed to the roar of revved-up engines. A procession of cloth-covered GMC Six-by-Sixes, their lights turned on for convoy formation, ground out through the gate and down to the highway, where a winterized jeep with a red flag was waiting.”
—Arthur R.G. Solmssen, Alexander’s Feast, (Boston: Little, Brown & Co., 1971), p. 83.