The Need for ... Speed title
Second Time’s a Charm for Jon Blumenthal’s All-Business ’72 GMC
BY ROB FortierPhotography BY Tim Sutton
“I read an article in Popular Hot Rodding about a C10 that Roadster Shop had built with their chassis that competed with—and beat—a bunch of high-end Pro Touring cars, and said to myself, ‘I have to have one!’ How cool would it be to have an old truck perform as good as a modern sports car?!”
Not only are Jon Blumenthal’s own words a real testament to both the quality and performance of Roadster Shop’s chassis, but they’re also words echoed by many others these days as to why they’ve built/had built the trucks we’re seeing more and more of: pure, performance-minded “old trucks.” But Jon’s ’72 GMC didn’t quite start out on a positive note. As he tells us:

“I had originally purchased a different truck from a builder out of Northern California who I’d hired to complete the build. Long story short, he ended up defrauding a bunch of customers—including myself—so I rented a trailer and drove 600 miles to retrieve the project.

blue '72 GMC truck
collage of images of a blue '72 GMC truck
interior of a blue '72 GMC truck
blue '72 GMC truck
steering wheel in a blue '72 GMC truck
engine in a blue '72 GMC truck
blue '72 GMC truck
“Upon getting it home, I had to reassess the situation. The builder hadn’t gotten nearly the amount of work completed that was portrayed in the pictures he’d provided: the metalwork that had been done was not completed properly; bodywork was started on the cab even though the metalwork was not finished (just to show ‘progress’). At this point I had the chassis, engine, transmission, brakes, and a bunch of other go-fast goodies, but just a shell of a truck that was far from being complete.
bed of a blue '72 GMC truck
“After getting burned so bad I figured that I would tackle the project myself. While I am mechanically inclined, the amount of metalwork needed was a little out of my wheelhouse, so I decided the best way to move forward was to find another complete truck to use my parts on. The search took a few months to find the perfect candidate, but in my daily searches I finally stumbled across a very original, 80,000-mile, medium blue ’72 GMC on eBay … needless to say, I bought the truck and began what ended up being a 2 1/2-year project!”
rear of a blue '72 GMC truck
With the help of Hot Rods & Custom Stuff (inner fender work front/rear and freshened up the firewall) and Old Town Upholstery, both in Escondido, California, Jon’s “performance-minded” project finally became reality in April 2020, just as the pandemic hit—but that hasn’t stopped him from enjoying the fruit of his labor.

Along with the aforementioned Roadster Shop Fast Track coilover-based chassis his GMC is powered by a rather healthy Mast Motorsports 427ci LS7 backed by a QuickTime-adapted TREMEC T56 linking to a Strange Engineering 9-inch via QA1’s carbon-fiber driveshaft. Behind a quartet of gold-coated, 19/20-inch Forgeline Rodster wheels, Jon selected AP Racing’s 355mm/six-piston (front) and 340mm/four-piston Radi-CAL hi-po disc brakes managed by a Tilton 600 Series tandem pedal assembly (and his foot, of course!).

The LS7 features a Holley single-plane 4-bbl LS intake matched with their 1,000-cfm 4-bbl throttle body and HP controller, Ultimate headers with SpinTech–fabricated mufflers and Vibrant Performance resonators, and a Drive Junky serpentine front drive system. The American Powertrain T56 uses an all-Tilton clutch system, while the 3.70-geared rearend features MillerBuilt semi-floater with the Strange axles.

As Jon noted, the eBay score GMC was indeed so nice that nothing was done to the original-paint exterior. However, modifications were done to the bed floor to accommodate the chassis, and a raised transmission tunnel was spliced into the cab to accommodate the positioning of the six-speed and driveshaft.

Speaking of the interior of the cab, that’s where things went as far from OE as possible before Jon’s project hit the road (and track) once and for all. For starters, the gauges were swapped out in favor of Dakota Digital’s HDX system, a RetroSound audio system was installed in the stock radio provisions, and a TMI dashpad was used. Steering is now comprised of an ididit column topped by a Billet Specialties wheel, while the seating arrangements are now Recaro Expert 5 buckets with three-point harness system. Finally, Old Town Upholstery did their thing with black leather and German square-weave throughout (the headliner is the OG plaid insert, however!).

front of a blue '72 GMC truck