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Restored and Refined: A 1970 GMC K15 Finds New Life as a Drag Racing Beast

Wendy Wilson September 01, 2023 Diesel World

Beefed Up ’70 GMC Gets New Life on the Track

This rig has seen some things.

A 1970 GMC K15 currently owned by fabricator and YouTuber Wyatt Stengel of Seffner, Florida, the truck has been driven through several generations of Stengels over the years, says Wyatt.

“My great uncle bought the truck brand new in 1970,” he says. “It has been passed down through the family.”

Most recently, it had a spate of accidents that led it to where it is today: a kick-ass drag truck.

“Unfortunately, the last few years it was on the road, it somehow turned into a magnet for ac-cidents,” Wyatt says. “One time while in the mountains hunting, someone came around a blind corner too fast and hit it. Then, in 2015, a drunk driver turned right in front of me, totaling the truck again. [Note to readers: Don’t drink and drive!] After that, it sat a few years before I de-cided to build a drag truck out of it.”

Wyatt is no stranger to the drag circuit. His dad used to drag race, which piqued the interest of a younger Wyatt. Wyatt also built some fast Hondas and a couple of other trucks and Jeeps be-fore rebuilding the K15.

“I built this truck to learn new skills, create something to race, and as an advertisement for my business,” he says.

Wyatt has been involved in this hobby for almost 10 years. We’d say he did a pretty good job with this orange-and-black attack truck.

“The reason for the black front clip is because none of the factory front sheetmetal could be saved after the last accident,” he says with a laugh.


OK, so what’s the foundation for this drag racer? A “stock-ish” frame made on 1 5/8 chromoly steel. Wyatt modified it with a tubular back half and a 25.6-inch certified rollcage. Steering mods include 3rd-generation Dodge rack-and-pinion steering to make it easier to turn the wheels.

To improve steering and track handling even more, Wyatt bumped up his front and rear sus-pension. In the front, his axle ratio is GM 9.25 IFS/3.42 with QA1 double adjustable front and rear springs, stock brakes, a homemade 4an brake lines, and a hydro boost from 2020 Du-ramax.

In the rear, the axle ratio is GM 10.5 14 bolt/3.42. He used Hyperco springs, QA1 double-adjustable shocks, IMS lightweight brakes with Wildwood calipers, a Yukon Spool locker, and a 4-link rear suspension. Wow! And for tires, he chose M&H 30×14 slicks/28×10.5 radials front and rear.


Something has to power this thing, and Wyatt knew just what to install. He chose an 03 LB7 V-8 Duramax engine with 1,900 lb-ft of torque and 3,400 rpm, and it boasts 1,300hp at 4,000 rpm. Displacement is 403cu. The crankshaft comes from Callies Compstar, the rods from Carril-lo, and the pistons from Mahle Forged. It uses a modified stock oil pump and a stock oil pan. The camshaft is a stage 2 alternate firing order cam, and it has a DHD high rpm water pump.

As for the fuel system, Wyatt chose an NCC Fab water-to-air intercooler, a VSRacing 85mm turbocharger with 75 psi boost, an Airdog 5G 220 mph lift pump, and an Exergy Performance 14mm CP3 injection pump. The injector comes from Exergy Performance with 250% overs. And the nitrous oxide system? It’s Nitrous Express that delivers a horsepower boost of 400.

This ride’s programming is a Bosch MS25 Standalone ECU that’s custom-tuned by Mark Broviak and Jeff Hale from Exergy. Additional electronics include a PCS2800 (tam), two PMU16s for power distribution, and AEM dash, and a 22-channel can module.

To direct those fumes up and away, Wyatt used 5-inch PPE and in-house crossover-to-turbo straight-pipe exhaust manifolds finished in polished titanium.

Keeping those RPMs low, the K15’s transmission uses a late-model 4L80e with a converter from Precision Industries, with a stall speed at 2,800 rpms. Joel Knauber out of Wisconsin per-formed all the trans mods, which included a custom driveshaft from Universal Driveshafts and a slightly modified NP241C transfer case.


Inside the cab, Wyatt made only a few changes. He added an AEM CD7 display to keep him posted on all his gauges, and he added an MPI steering wheel for a personalized driving expe-rience. He also did all the interior sheetmetal improvements himself.

All said and done, this resurrected and reborn K15 that took just three years to build shows that trucks stand the test of time—as long as there is a dedicated caregiver to give it new life.


Best Quarter-Mile: 8.76 seconds
Speed: 154 mph
Curb Weight: 4,445 pounds
MPG: 15


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