Courtesy of Engine Builder
The phrase “more than meets the eye” is something that comes to the mind often when considering diesel motorsports — to the average person, a 5,000 lb. truck looks much more akin to a utility vehicle than a racing machine. Even trucks with aggressive wraps and decals get skeptical looks when they power down the track at breakneck speeds. But even more unassuming are the trucks that don’t look like performance vehicles at all.
“Sleepers” are more common in the car community. Essentially, they are cars that are made to appear completely stock or modest looking on the exterior while housing performance upgrades under the hood. Every so often we find a diesel truck with an impressive sleeper build, and today’s Diesel of the Week is no exception.
Mark Rojee has been working on diesels for around seven years at Mahky’s Performance and Tuning. The small family-owned diesel performance and repair shop is nearly 3,000 sq.-ft., has a four-bay garage, and employs six workers, five of whom are mechanics. His father has owned the shop for 34 years, and Rojee first got into diesel work seven years ago. Before that he spent his childhood racing dirt bikes — Like most racers, he was essentially born into the performance world.
A few years back, he bought his first diesel truck: a 2018 Ram 2500. The 4th-gen truck looks humble on the outside, with a factory white paint job and nothing to indicate anything more than a stock truck. But under the hood, Rojee is hiding a 1,500 HP monster that converts his modest workhorse into a racing machine.
The 6.7L Cummins is an Enforcer series engine, built by none other than the guys over at D&J Precision Machine. The engine platform has won multiple Ultimate Callout Challenge competitions. The engine is based on a cast-iron block that’s been sleeved, fire-ringed, fitted with a deck plate, and equipped with an X-beam rods, cast-aluminum pistons, and a HD girdle. A billet flat tappet cam, Hamilton billet lifters, and 7/16-inch diameter pushrods make up the valvetrain.
The cylinder head is a fire-ringed Stage 3 with oversize valve that flows much better than the factory unit thanks to 115-lb valve springs and titanium valve spring retainers. 9/16-inch Arp head studs torqued to 175 ft./lbs. fasten the unit to the block.
