LIVING PROOF THE 7.3L ISN’T EXTINCT JUST YET
Back before super-sophisticated, computer-controlled, high-pressure common rail fuel systems like today’s Piezo injectors and CP4 injection pumps came around, the 7.3L Power Stroke was a great option for the 3/4-ton truck market. Back then, GM had the 6.5L Turbo Diesel some of us would like to forget ever happened, Dodge was steamrolling the market with their mechanically injected 5.9L Cummins, and for Ford fans, the 7.3L Power Stroke, with its Hydraulic Electronic Unit Injector (HEUI) and it’s 275 hp, was a welcomed sight.
However, by today’s standards, the 7.3L is outdated technology with limited horsepower potential, so opting for such a dinosaur to power a dedicated drag truck seems odd. And yet, for Dennis Schroeder, co-owner of Strictly Diesel in Phoenix, AZ, the 7.3L Power Stroke is what he knows. It’s a powerplant he’s extremely familiar with and, when it comes to being consistent at the drag strip, familiarity can be one of your best friends. Racing is all about making power, being consistent with that power, and being confident in how your vehicle will react pass after pass. While the 7.3L isn’t an obvious choice for a drag race application, it was always the obvious choice for Schroeder.
After starting his own diesel performance business in 2001, Dennis and then, ITP Diesel, focused on developing and offering well-engineered performance fuel system parts and simple bolt-on upgrades specific to the 7.3L Power Stroke. He made a name for himself throughout the Power Stroke community for offering some of the best 7.3L products available and became the go-to vendor for performance shops all over the country looking to improve the 7.3L platform in customers’ vehicles. Because of his knowledge in the Power Stroke, when it came time to get back into drag racing, something he’d been involved in from a young age, it was an easy choice for him. Building a high performance 7.3L was what he knew, and in 2006, when the truck build started, it wasn’t quite the dinosaur it’s considered today.
While the truck has gone through quite a few changes over the course of the last 13 years, it was really pushed to a full-blown, track-ready drag truck around 2010. At that point in time, Dennis was merging his business with close friend Nate Brekken at Strictly Diesel. Brekken’s shop focused on local diesel repair, and Dennis brought a performance-oriented, nationwide customer base. Together, the pair turned Strictly Diesel into a major name in the diesel performance business, and this truck may have helped make it happen.
Standard Cab Shorty
Starting off with the 2WD, F250 chassis, the frame was shortened up enough to fit a factory short-bed to help reduce overall weight and help with weight transfer. The factory steel hood, fenders, and doors were replaced with fiberglass pieces from GTS to allow maximum weight loss. The factory glass windshield remains, but the door glass and rear window were replaced with Optic Armor Lexan pieces. A complete roll cage was fabricated and installed for safety as well, along with a single race seat with Crow a 5-point harness. The rear suspension was modified by removing the factory leaf springs for a fully adjustable dual ladder bar suspension with pan hard bar. Factory shocks were replaced with double-adjustable, custom-valved AFCO shocks built specific for drag racing. The rear axle was converted to a 3.55 gear ratio with a welded Detroit locker. To aid with staging and holding the power back on the line, Schroeder also installed a second set of factory brake calipers and pads to the rear axle. The front suspension remains close to factory, with just the addition of Chassis Tech’s 3” drop I-beams and custom-valved QA1 single-adjustable shock absorbers. For traction, the truck sits on M&H Racing 31×12.50 Nostalgia slicks and 16×10 Bogart Racing aluminum wheels. The front tires are 225/75R16 Goodyear Wrangler ST’s on matching 16×6.5 Bogart wheels.
Under that custom fiberglass one-piece front clip, you’ll find a highly worked-over 7.3L Power Stroke engine. Built by Zane Koch of Wide Open Performance, the long block was assembled in 2010 and has countless 1/4-mile passes on it since that time. Using a cryogenically treated stock engine block, it was bored and sleeved to factory specs, and the water jackets were then filled with Hardblok to help stiffen it up as much as possible. A WOP main stud girdle and ARP studs helps reduce main cap walk. The camshaft has been modified for more lift and was also cryogenically treated. Crower billet connecting rods were used to handle the abuse as well. Cast Mahle pistons were machined out for lower compression, and valve reliefs were cut to clear the big race spec’d camshaft that was installed. The factory low pressure oil pump was upgraded with a Melling unit, and the entire rotating assembly was balanced. Cylinder heads were also assembled by Wide Open, with hand port and polish, hardened pushrods, and hi-rev valve springs.
For fuel, Dennis uses one of his Driven Diesel regulated return kits and an Airdog 150 feeding into a Fuelab 41401 high-pressure fuel pump. The injectors are a 400 cc, 200 percent nozzle Hybrid variation from Swamps Diesel. The high-pressure oil system had to be upgraded to support those big injectors, so a dual Terminator Engineering HPOP system was installed in the valley of the engine and can maintain 3200-psi injector control pressure without issue. The truck also runs a full competition-style, high-pressure Hypermax water injection kit, controlled by an onboard data-logging system, which is used to help keep all that fuel from torching the cylinders with too much EGT. To create enough air, a one-off, custom-compound turbo system was installed with turbochargers spec’d by Bell Turbos of Corvallis, OR. The custom 72 mm, K31 high-pressure turbo is mounted on a Hypermax pedestal and is fed by a custom Holset HX82 low-pressure unit that provides up to 30 psi to the overall 80-psi boost pressures depending on waste gate settings. Stainless steel tubular headers feed exhaust to the turbine side of the turbos, and a custom 5” hood stack with mini-wastegate dump is all that’s needed for an exhaust system.
Backing all that horsepower and transferring it to the rear axle is a fully built 4R100 transmission assembled by John Wood, with a custom 2500-stall, 13” Suncoast torque converter. The transmission is controlled by a stand-alone PCS controller system tuned and calibrated by Dennis himself. The PCS system also offers complete data logging that can be used to fine tune the setup after every track pass. Dennis also handles most of the engine tuning himself using a Moates Quarterhorse emulator. To make launching and 60-ft times more consistent, he also designed and programmed his own launch control box. While the truck has never been on a chassis dyno in its current form, track times and vehicle weight are enough to calculate horsepower to be just north of 800 hp on fuel only, which is a very respectable number for such an outdated and uncommon performance-oriented powerplant.
At the end of the 2018 race season, Dennis was on a high after winning an NHRDA event in Denver, CO, and running a personal best of 10.95 at 124 mph, but the motor showed some signs of hurt when motor oil doused the engine bay and undercarriage. It’s suspected that after 100+ passes and eight years of racing, a cracked piston might lead to an engine overhaul and some changes for the upcoming 2019 season. Dennis is making plans for camshaft, compression ratio, and injector changes to better fine tune the overall combo for the specific needs of the truck in his preferred index classes. He also has plans to make some changes to the weight and balance of the vehicle by moving the batteries and cooling system behind the rear axle. Dennis gives credit for the truck’s success and build to his close friends Nate Brekken, Tim Mitchell, Chaz Lightner, John Wood, and Zane Koch. Dennis knows he couldn’t have done any of it without their help. While a hurt engine would lead some to look at finally updating to a more modern engine like the latest common rail 6.7L Power Stroke, he is going to stay true to his roots and continue proving that the old 7.3L dinosaur may be nearing extinction, but it will never be dead as long as he has anything to say about it.