The Blazer is a full-size sport-utility vehicle that General Motors marketed from the 1969 to 1994 model years. A variant of the C/K truck line, it was a shortened version of the half-ton pickup, and GMC sold the same vehicle from 1970 to 1991 under the Jimmy name.
GMC Blazer at a glance
| Class | full-size sport-utility vehicle |
|---|---|
| Production | 1969-1994 model years |
| GMC version | GMC Jimmy, 1970-1991 |
| Based on | half-ton K10 pickup, wheelbase shortened from 115 to 104 in |
| First generation | Action Line, 1969-1972 |
| Second generation | Rounded Line, 1973-1991 |
| Drive | four-wheel drive at first, rear-wheel drive from 1970 |
| Engines | 250 and 292 straight-six, 307 and 350 V8 |
| Gearboxes | three-speed automatic TH350; three- or four-speed manual |
| Transfer cases | Dana 20 or NP-205 |
| Ground clearance | 8 in, approach angle 35 degrees |
| Replaced by | GMC Yukon for 1992 |
Based on one source, the English Wikipedia article on the Chevrolet K5 Blazer, which covers the same vehicle GMC sold as the Jimmy. The photograph shows the Chevrolet-badged version.
History of the GMC Blazer
First generation (1969-1972)
GM developed the Blazer to compete with the International Scout and the Ford Bronco while also improving on-road behaviour against the Jeep CJ-5. The half-ton K10 pickup served as the basis, with its wheelbase shortened from 115 to 104 inches. The result was larger than the Bronco and the Scout and offered more cargo space, better on-road handling and a large degree of commonality with the C/K pickups, which kept production costs down. For its first model year it was available with part-time four-wheel drive only; a removable hardtop or a soft top could be specified, and passenger seats were optional on the base model. For 1970 a rear-wheel-drive version was added and the same vehicle was rebadged for GMC as the Jimmy.
Mechanical layout
There were four engines, matching the pickups: the 250 and 292 straight-sixes and the 307 and 350 V8s. Buyers could choose a three-speed Turbo-Hydramatic TH350 automatic or one of two fully synchronised manual gearboxes, a three-speed or the four-speed SM465 with its 6.55:1 granny first gear. The four-wheel-drive version had a solid front axle with leaf springs front and rear, while the two-wheel-drive version used independent front suspension and rear trailing arms with coil springs. Both had drum brakes until 1971, when the whole GM light truck line gained front discs. Two transfer cases were offered, the Dana 20 and the NP-205. Ground clearance was 8 inches and the approach angle 35 degrees.
Second generation (1973-1991)
For 1973 GM redesigned its full-size trucks, a generation known internally as the Rounded Line and by the public as the square body. A tilt steering wheel became optional. Rear-wheel-drive versions were built until 1982, but most buyers chose four-wheel drive. Popular Science tested a 1973 Blazer with the 175 hp 350 V8, automatic transmission and full-time four-wheel drive: it reached 60 mph in 22.5 seconds and returned 9.648 mpg at a steady 45 mph. From 1983 the S-Series Blazer and Jimmy took the compact end of the range, and to avoid confusion GM called the full-size models the Chevrolet Full-Size Blazer and the GMC K-Jimmy, later V-Jimmy.
Successors
For 1992 GM redesigned its full-size SUV line and GMC renamed the Jimmy as the Yukon. The full-size Blazer itself was replaced for 1995, when the Chevrolet Tahoe arrived as a shorter-wheelbase version of the Suburban. The Blazer name was later revived for a mid-size crossover.
Design and features
- Removable top: the first two generations were half-cab pickups with a removable rear roof.
- C/K commonality: mechanical parts were shared with the full-size pickups, keeping the price down.
- Two- and four-wheel drive: a rear-drive version joined the range in 1970.
- Off-road gearing: the SM465 manual had a 6.55:1 granny first gear.
- Optional luxury: automatic transmission, radio and air conditioning were available from the start.
GMC Blazer versions
- K5 Blazer (1969-1994): the Chevrolet-badged full-size two-door.
- GMC Jimmy (1970-1991): the same vehicle sold by GMC dealers.
- Soft top or hardtop: buyers chose a convertible top or a wagon-style removable hardtop.
- Two-wheel-drive Blazer: added for 1970 and built until 1982.
- Full-Size Blazer and K-Jimmy (1983-1991): the official names used once the compact S-Series arrived.
The Blazer shared its platform with the GMC C/K pickups and with the longer GMC Suburban, and it was replaced by the GMC Yukon. More trucks are in the GMC collection.
Sources
- Chevrolet K5 Blazer, English Wikipedia: generations, engines, GMC Jimmy naming, dimensions
