RESTORING A 1970 GMC C2500 CUSTOM CAMPER
Dave Plummer is hardly the first enthusiast who went looking for one model of vehicle, only to shift gears and end up with something else, but his story is an interesting evolution, nonetheless. “I had been searching for years for a ½-ton 1967-’72 big-block short bed GMC Sierra Grande – a ‘muscle truck’ of sorts, but never found one. In the meantime, I stumbled onto this one-owner ¾-ton Longhorn, and for about half a second contemplated shortening it,” explained Dave. Quickly however, the heavy-duty and distinctive nature of the long GMC reeled Dave in, and a return to original condition ensued.
Much of the motivation for a stock restoration hinged on the GMC’s well-preserved condition. Credit for that goes to original owners Fred and Jessie Klotthor, and a life spent in California. The Klotthors rolled up slightly over 100,000 miles on the truck through the years, and family photos revealed that a small camper was often used during summertime vacations to various destinations across the U.S. Dave has connected with some of the Klotthor’s extended family, and grandkids fondly recall camping and riding in the camper on the GMC. We’re told there was even an intercom fitted between the camper and the truck cab, and while that doesn’t sound high-tech today, some would have considered it cutting-edge in the day.
The truck was a great rust-free example of what might be considered GMC’s ultimate carrying and camping platform. For starters, there’s an unusual bed configuration which in Chevrolet-speak, was called a Longhorn. Available only on ¾- and 1-ton two-wheel drive pickups, the Longhorn stretched the standard bed and wheelbase from 8 feet (127 inches) to 8.5 feet (133 inches). While Chevrolet even saw fit to install Longhorn emblems on such trucks, GMC did not. In fact, GMC doesn’t seem to have used any terminology beyond “133-inch” in their literature, though the hobby tends to generically call all GM 133-inch wheelbase pickups "Longhorns".
Beyond the extended wheelbase and bed, the ¾-ton Longhorn frame is the same as the 1-ton, and in this case is fitted with the L47 402-cu.in. big-block Chevy engine. The 402 was a new displacement for Chevrolet/GMC cars and trucks in 1970 and was essentially the 396 from earlier years with a .030-inch larger bore. Oddly, the 402 was never accurately identified on fender badges. For example, most cars continued with their 396 emblems, while trucks like Daves displayed “400” callouts. We’re left to guess that the minimal bump in displacement just didn’t warrant recognition in the eyes of GM advertising execs and bean counters. When new, the rest of the drivetrain in this truck consisted of a Turbo 400 automatic transmission and a Dana 60 rear differential containing a 3.54:1 gearset.
Other options on the original spec sheet include GMC’s top trim package, the Sierra Grande. That trim level consisted of a more deluxe interior, chrome front bumper, interior and exterior brightwork, and several other small items. What wasn’t standard on any of the trim packages was the bucket seats and console that are original here, though interestingly, buckets were promoted in 1970 GMC literature as a luxury item. Today, most enthusiasts view buckets as more of a sporty orientation, but they’re a rare and desirable option no matter your view.
Dave brought the GMC to his home garage in 2011 and proceeded to completely disassemble it. The extra-long frame was stripped and powdercoated, suspension rebuilt and detailed, and front disc brakes from a ’72 model were added for better performance and safety. The original “Invader V-8” engine was rebuilt by Rick at Preston Automotive, who in an earlier life was a NASCAR engine builder. It’s close to stock, down to the original carburetor and exhaust manifolds, but with a .030-inch overbore and hardened exhaust seats. The original Turbo 400 has been shelved in favor of a more current 4L80E unit, along with a 4.56:1 gearset and a helical locker in the Dana 60. As Dave puts it, the combination has “a lot of grunt,” and ends up with a significantly steeper first gear than stock, along with lower RPMs over the highway.
The blue interior is a great look with the two-tone exterior, and the factory buckets really make the combination. All seemed good when Dave turned the seats and reproduction upholstery from LMC over to an unnamed upholstery shop, but things didn’t go so hot. When he picked the seats up, he found the factory contours and bolstering were gone, resulting in something akin to “van seats.” Dave proceeded to pull the assemblies back apart, only to find that the shop had discarded the wires and springs that gave the seats their shape. He wound up recreating much of the support structure, and in the end reinstalled the seat covers with the desired results. While the truck was originally equipped with full instrumentation, Dave did choose to add an optional speed warning speedometer during the restoration.
Dave is clearly a hands-on guy who enjoys wrenching on his own cars and projects, and the bulk of the previously mentioned efforts he performed in his well-equipped garage. However, when it came to body and paint work, this is the stuff he leaves to the professionals. “Once I had the chassis done, I set the cab and bed back on the frame and shipped it as a unit to Muscle Car Restorations in Chippewa Falls, Wisconsin.” While he no doubt could have had similar work performed locally near his Seattle area home, Dave has a relationship with the crew at Muscle Car Restorations due to previous projects. Trust in the outcome was critical, and for Dave, it was worth the effort and cost to send the truck most of the way across the country.
At MCR, the truck was stripped to metal, and repaired in just a few necessary spots. All evidence of two fuel doors from the auxiliary fuel tanks that had once been installed, are gone. Likewise, Dave chose to have a seam eliminated on the exterior front of the bed, where GM added an extension that stretched the bed length to 8 ½-feet. The factory finish in this area was utterly utilitarian, while Dave’s intent for his GMC rose a bit higher.
Once the truck came back to Dave’s home wearing its new two-stage finish in original colors, the remaining work could commence. Evidently all Longhorn beds were built using a wood floor, whereas standard beds could be had in either wood or steel. Dave says the factory simply painted the wood in body color, but like many who traveled the road before him, Dave decided to make it look nicer with a combination of stained planks and chromed hardware.
A myriad other reassembly tasks ensued. The list included a thorough cleaning of the original fuel tank and lines, rebuilding the original air conditioning system to include a new aluminum compressor, refinishing and replacement of worn interior components, powdercoating the factory 16.5-inch rims, and much more. The new aluminized dual exhausts feature quiet Dynomax mufflers, which seem close to the original tone according to Dave.
“This truck isn’t exactly what I started out looking for, but I sure consider myself fortunate to have found it. It starts, runs, and drives just like a new 1970 truck would have. It turned out as good as I could’ve hoped for, and I’ve turned into a big fan of these heavy-duty workhorses. There were plenty of them built in the day, but you sure don’t see many anymore,” says Dave. Thanks to Dave Plummer, we’re getting a rare look at one of the best!