Old Iron
GMC Gets on the SUV Bandwagon
Chevrolet made a big splash in 1969 with the introduction of the Blazer. GMC followed with their version of the new platform for 1970 and called it Jimmy. The ’70 GMC line was the first year for the badge engineered GMCs. Despite sharing many components with Chevrolet trucks, GMC had long maintained some distinct differences, most notably in their powerplants. By the late ’60s GM Corporate execs began to fixate on the financial benefits of merging all the light trucks into one basic platform and simply rebadging them.
A few GMC execs had long fought to retain some individuality between the two brands but by 1970, the battle was lost. Gone was the incredibly torquey and durable 305 cubic inch V6 that had been the last vestige of GMC individuality. While the Jimmy had some detail differences with its brother Blazer, it was the same truck. In general, the GMC truck line did offer a few different options from Chevy that were geared a bit more towards commercial or go-towork pursuits. The Blazer and Jimmy were perhaps even closer in all areas than the trucks, though fortunately these “twins” wore slightly different clothes so you could tell them apart. The bare bones Jimmy came topless and you ordered either a soft top or the fiberglass hardtop... if you wanted a top.
The Chevy 250ci six came standard in the KS models, with a 307ci two-barrel standard in the V8 KE models and a 350ci four barrel optional. Trans. options ranged from a ho-hum three-on-the-tree, through a beefy Muncie four-speed and the TH-350 automatic. It isn’t clear how popular the Jimmy was versus the Blazer, but overall, the design was a good seller and the body style of the ’67-72 Chevy and GMC trucks has become a classic and a big-time collectable. The Jimmy shares this popularity, especially since it’s something a little different from the “run-o-the-mill” Chevy (please don’t kill me!). The 1970 Jimmy you see here was a “love at first sight” purchase from its original owner by current owner Gary Knight in 1995.
It was in great shape when purchased and was almost totally original. Gary said he took the top off in 1996 and it’s never been back on. In ’98, he found some rust and decided to fix it. Let’s just say Gary got a little carried away. Six years, $18,000 and a complete teardown later, he had it up state you see it today. It started out as a KE truck with the Custom option, hardtop, 350 V8, 3.73:1 gears, factory air, power steering and brakes.
In the course of the resto, Gary added some factory options, to include tilt steering, an original AM/FM radio, roll bar, tow hooks, tach and vacuum gauge. The only non-stock additions are the sharp looking GM Rallye wheels and 31 x 10.50-15 Uniroyal Laredos and dual exhaust. Don’t know about you, but this writer would pay to go cruising in this babe... and likely have to be hunted down to give it back!
A clean look, inside and out, is part of what makes these trucks so popular. Here you see a pretty much decked out ’70 with all the options. The rather odd place for the speaker, below the HVAC controls, is original. The upholstery is the factory original Sandalwood material. Not all trucks look great topless, but this one does. This Jimmy has the Custom option and for the $358 it cost, you got some extra chrome trim, bucket seats, a right armrest, color keyed floor coverings... and a “Custom” badge. B.C. Automotive, of Bloomfield, Ohio, applied the Light Quasar Blue Metallic paint. That’s a pretty good match for the original Medium Blue Poly. The Jimmy was fairly well endowed in the drivetrain area. A Dana 44 front, unfortunately with the small 260 U-joints (easily upgraded), was fed by a TH-350 trans in front of a NP-205 t-case. The rear axle was the Saginaw 12-bolt that was available with a Posi limited slip. The interior is roomy and that was one reason why the two-door SUVs grew in size from the Jeep, Scout and Bronco-sized rigs. The loss of trail performance, what little there was, was not felt by the majority of buyers, but a cramped interior was a big complaint among SUV buyers and the Jimmy/Blazer addressed that very well. The 255 hp (gross, 200 hp net) 350ci four barrel was the same engine option available in the El Camino and similar to many car engines. For quite some time, the Jimmy/Blazer was the most powerful short wheelbase SUV you could buy. The power was welcome by all, but one of the few complaints was that this engine needed premium fuel, especially when towing. It had a relatively high compression ratio of 9:1 and tended to ping on regular. The 307 V8 was in the same ballpark. In 1971 the compression ratio was dropped to 8.5:1 and that ended the complaints. That drop in CR came with some emission controls as well and net power dropped to 170 hp but torque stayed the same.