Prior to GMC introducing a specific model called a Jimmy in late 60s, were GMC trucks in the 40s, 50s and 60s commonly referred to as Jimmys (nickname) when referring the make?
This is all I could find, and not even from a GM source
1969-1972
First generation
Also called GMC K5 Jimmy
Model year(s) 1969–1972
Body style(s) 2-door SUV
Engine(s) 250 in³ I6
292 in³ I6
307 in³ V8
350 in³ V8
Transmission(s) 3-speed TH-350 automatic
3-speed manual
4-speed manual
The original K5 was a short wheelbase truck. It was available in 1969 as 4-wheel drive only; in 1970, a two-wheel-drive model was offered. There were four choices for power plants: the 250 in straight-6, the 292 straight-6, the 307 V8, and the 350 V8.
The Blazer was designed and marketed to compete with International Harvester Scout and the Ford Bronco. Both of these were originally aimed at the short Jeep CJ series, which were much smaller than other trucks. The great innovation of the Blazer was to simply offer a shortened pickup truck, which both increased interior space, and lowered the cost of production with a shared platform. The Blazer quickly became popular. For the first time, it married the off-road capabilities of the Scout with the "luxury" features like air conditioning and automatic transmissions routinely available on pickup trucks. By 1970, the Blazer was already outselling both of its older rivals. Ford, Dodge, and even Jeep would counter with similar shortened pickups, with the Dodge Ramcharger and Jeep Cherokee.
The two-wheel drive version came with independent front suspension and rear trailing arms, both with coil springs. The four-wheel drive version had a solid front axle and used leaf springs front and rear. Both versions used drum brakes at all four corners until 1971, when the entire GM light truck line got standard front discs.
There was also a choice between a three-speed automatic transmission Turbo Hydromatic (TH350), a three-speed manual transmission, and a four-speed Synchromesh (SM465) manual transmission. Two transfer cases were offered: the Dana 20, available only with the manual transmissions, or the NP-205, available with both types of transmissions.
