A Slight Role Change

When building a go-fast drag truck, most start with the lightest platform and work from there. But Chase Lunsford is not most people. The co-owner of Kingspeed Race & Repair in Bowling Green, Kentucky, had been wrenching on his five-speed manual 2001 Dodge Ram 3500 dually for years, before he decided to get serious. The Kingspeed team decided to go Pro Street racing and knew they had their work cut out for them.


Lunsford relies on a huge single 88mm S400 BorgWarner to build boost for his Cummins.



Supplying fuel to the engine are a pair of Fleece Performance Engineering PowerFlo 750 CP3 injection pumps. By looking below the fuel rail, you can see the Kingspeed billet aluminum-machined intake manifold replacing the intake shelf on the Cummins head.
When Lunsford wanted more nitrous he installed the bottle for the third “big kit”.

Soon after moving up to the Pro Street class, Kingspeed partner Michael Cordova cut the frame in half while Lunsford was away, beginning the Pro Street effort. Lunsford, his wife Elizabeth, Steven Cole, and Cordova went to work on building the truck into what you see here today: a purpose built Pro Street diesel drag racer that finished second in the ODSS Pro Street Championship battle for both 2015 and 2016 while taking home wins at the Scheid Diesel Extravaganza and the Rocky Top Diesel Shootout.



The Kingspeed crew performed a “back-half” conversion by removing the rear section of the 3500’s frame near the transmission crossmember. Chromoly tubing replaced the factory structure and provide mounting points for the rear suspension. Ditching the heavy full-dually bed in favor of a set of SRW bedsides maintained a factory look. But from the rear, the entire lattice work of chromoly tubing is visible.

Inside, Lunsford’s truck is all business. Stripping the factory interior saved weight and made room for the NHRA-certified roll cage, race seat, and safety harness.



For improved strength and weight reduction, chromoly tubing replaced the rear frame rails and crossmembers.
Peeking through the network of chromoly tubing, you can see the rear-mounted nitrous oxide bottle supplying additional power.

DW-1706-KING-24For safety and to further stiffen the chassis, Lunsford and his Kingspeed team installed an NHRA-certified 8.50-second roll cage in the cab with support bars that come down to the rear portion of the chassis through the tinted Lexan rear window. Stripping the interior increases room for the roll cage. Then, they installed a Corbeau FX1 Pro race seat as well as a set of Simpson five-point race harnesses. A quick-release steering column and lightweight racing steering wheel keep the truck pointed in the right direction. The build team used Lexan to replace the windshield, saving weight and offering a safer alternative for track use. Wrapping the truck in metallic-gray vinyl, adding gold Kingspeed graphics, and applying the sponsor logos completed the body modifications.

Power to Pavement

Up front, the 4WD truck puts power to the ground with the stock Dana 60 axle assembly and a set of factory coil springs that were cut down for a better ride height, as well as double-adjustable QA1 shocks. In the rear, the build team installed a Moser Engineering M9 fabricated rear axle assembly for a huge weight reduction over the factory dually axle. The M9 is located with a wishbone link up top and a set of Competition Engineering ladder bars on the sides. Ride height and suspension tuning are determined by a pair of Strange Engineering double-adjustable coilover shocks.

Sticky 29×13.50x15LT Hoosier Quick Time Pro drag tires are wrapped around lightweight 15×10-inch Holeshot racing wheels.

The truck rolls on Hoosier 29×13.50x15LT Quick Time Pro drag tires wrapped around lightweight 15×10-inch Holeshot racing wheels. In addition to the NHRA-mandated parachute mounted to the rear of the chassis, Lunsford relies on upgraded wheel brakes with Wilwood 6-piston calipers and rotors up front and dual 4-piston Moser calipers and rotors on each side in the rear to whoa down the 4,560-pound truck at the big end of the track.

6.7L Cummins

Upon completing the chassis modifications, the Kingspeed team needed a potent powerplant to push the truck down the track. Starting with a 2008 Cummins block, they built a 6.7L high-compression, common-rail race engine. The heart of the engine is a Cummins crankshaft that swings Kingspeed connecting rods and 20:1 Diamond pistons that were built to Kingspeed specifications. A Kingspeed roller cam actuates 1mm oversized valves in the Competition cylinder head with the intake shelf milled off and replaced by a billet aluminum-machined intake manifold.


Chromoly tubing replaced much of the factory frame, starting near the rear of the transmission.

The original VP44 fuel system would not keep up with Lunsford’s go-fast plans, so he chose a common-rail option. It starts with a mechanical low-pressure pump drawing fuel from the rear-mounted aluminum fuel cell. It then feeds into a pair of FPE PowerFlo 750 CP3 high-pressure pumps. Then the high-pressure fuel is fed into the fuel rail and handed off to a set of Dynomite Diesel Products Super Mental fuel injectors. To enhance the engine further, the truck has two nitrous bottles and three kits of nitrous to boost performance on-demand.

Rather than go with a compound turbo setup, Lunsford and the Kingspeed team chose to keep it simple with a single BorgWarner S400 88mm turbo that’s fed hot exhaust from the engine through a Steed Speed Competition T6 exhaust manifold. A pair of large Turbosmart wastegates is employed to keep boost pressure in the desired range. Spent gases from the turbo and wastegates are directed up through hood stacks, while the compressed charge from the turbo is fed into a Mishimoto 6.0L Ford intercooler before returning to the engine through a Cummins intake elbow. Lunsford uses EFILive tuning to control the engine and estimates that it is making around 2,000 hp and 2,500 lb-ft of torque.

47RH Trans

To handle all that power, the Kingspeed team built a competition-ready Dodge 47RH transmission that is linked to the engine through an SFI-approved ATS flexplate and Diesel Performance Converters billet torque converter with a 3,800-rpm stall speed. A B&M transmission cooler mounted behind the cab near the fuel cell helps keep the transmission cool, while a B&M ProRatchet shifter handles gear selection. The combination ran a best quarter-mile pass of 8.61 seconds at 166 mph and a eighth-mile run of 5.41 seconds at 136.8 mph.


Since the end of 2016, Lunsford and his Kingspeed team changed the race team and opted to sell the truck. This was to make room for the new build—a Pro Mod tube chassis truck to campaign through the 2017 season+. We look forward to seeing the new ride and will bring shots of it as soon as we can. Don’t forget about this former dually; we expect to see the new owner Seth Higgins tearing up the track with it on a regular basis! DW

If you’re building a drag-racing truck, here’s some tips and useful insights: Drag Racing 101

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