We’ve heard it a hundred times, but the story never gets old. After attending a national diesel event, a young man begins digging into his daily driver, realizes how easy (and cheap) it is to add horsepower and instantly becomes addicted. Meet David Keyser and his ’97 F-250. When he bought the old-school Ford, it’d been old-man-owned, garage-kept and the 7.3L Power Stroke under the hood was bone-stock. Now, a fully-built engine sees 55 psi of boost on a regular basis and the truck sends nearly 700hp and 1,300 lb-ft of tire-shredding torque to the pavement. It’s still David’s daily driver, but those trips to and from work are much more entertaining than they used to be.
Once he’d reached the breaking point of the 7.3L’s factory internals, there was only one choice: build the engine and forge ahead. Dialing things back and living conservatively wasn’t an option for David. He pulled the engine, tore it down and had the crank and block checked out while the heads were treated to a valve job and port work. Fresh back from the machine shop, he assembled the long block with the toughest parts in the industry, stuffed a set of some of the biggest injectors you can buy under the valve covers, ordered a 72mm turbo and told his tuner to work his magic. Below, you’ll find out just how David prepped his 225hp factory-rated 7.3L Power Stroke to withstand 700rwhp day-in and day-out—along with an occasional blast of nitrous.
Built 7.3L
After bending a factory rod with the truck’s previous setup, David pulled out all the stops during the rebuild. Not only did he opt for a set of forged-steel Manley connecting rods, but he also installed an Irate Diesel main girdle, ARP main studs and fly-cut standard bore pistons. Above the O-ringed head gaskets you’ll find a set of ported cylinder heads from Crutchfield Machine with 165-lb valve springs and ARP studs anchoring them to the block. The factory fuel bowl and turbo mount have been ditched in favor of an electric, frame-mounted fuel system (with regulated return) and one of Irate Diesel’s T4 turbo mounting systems.
S400 SX-E
Thanks to the aforementioned Irate turbo mount affording David the ability to run any T4 turbocharger he wants, he went big. The box BorgWarner S472 SX-E at the back of the valley sports a 10-blade, forged milled compressor wheel with a 72mm inducer, an 87mm turbine wheel and a 1.0 A/R exhaust housing. Once through the truck’s CSF intercooler, 55 psi worth of boost makes it into the engine at full tilt. Vibrant Performance clamps keep all attachment points for the intercooler piping solid.
Hydraulically Actuated Fuel System…On Steroids
Big injectors are the key to any 7.3L making respectable power, so David opted for a set of 350cc hybrids, with nozzles that flow 200-percent more than stock, from Full Force Diesel. To keep the oil side of the 350/200 injectors happy, a Gen3 high-pressure oil pump from Swamp’s Motorsports is employed and mounts above the factory, 196,000-mile unit in the lifter valley.
Self-Built Transmission
Having pieced together his fair share of performance Allison 1000 automatics, David had no reservations about taking a stab at prepping his E4OD for big power. The four-speed slushbox has been treated to a billet input shaft, steel six-pinion planetaries, a TransGo shift kit, Alto clutches, a Twisted Diesel valvebody and a RevMax triple-disc torque converter. A Derale flow-through pan and a remote mount, electric auxiliary cooler ensure ATF temp never exceeds 185 degrees.
Power. Planted.
Trying to send 700hp and 1,300 lb-ft to the pavement would be futile without a set of quality traction bars. After scoring a set off of a friend’s Duramax, David had bolt-on axle mounts made and repurposed them for his OBS. Now axle wrap is non-existent at the track and on the street. Also notice the Baldwin water separator and fuel filter, which are part of an electric fuel system from Irate Diesel Performance that makes use of a Walbro lift pump.
Analog Gauges & Custom Tuning
A quartet of A-pillar gauges from Isspro allow David to keep an eye on fuel supply pressure, boost pressure, exhaust gas temperature and transmission fluid temp. The digital display switch next to the bottom gauge is part of the Power Hungry Performance Hydra Chip that’s attached to the truck’s PCM. Custom tuned by longtime 7.3L enthusiast Brian Jelich of Jelibuilt Performance, it allows David to navigate through a plethora of custom-tailored calibrations, all designed for his specific parts combination.
Traction & Bling
For a good all-around street tire, David runs a 285/50R20 Nitto NT420S at each corner. While the 420Ss out back have their work cut out for them when the big S472 lights and the truck’s peak torque hits, the all-season tread provides a quiet, comfortable ride and traction that’s sufficient enough for most situations. The 31-inch Nittos mount to 20x12-inch Blade SS8 polished-aluminum wheels from American Force.
The Bait
With a diesel-powered ¾-ton ’92-’97 body Ford not being your typical hot-rod, this license plate probably perplexes most people that lock eyes with it. Other than this little hint and the truck’s traction bars, no other visual cue on the truck indicates you’re next to an 11-second performer.
On the Dyno
Aboard the chassis dyno at Bean Machine in Woodbury, Tennessee (a load cell Dynocom that’s known for its accuracy), the hottest tuning file in David’s arsenal allowed the truck to clear 687rwhp on fuel. With adequate traction, David plans to run 11s in the quarter-mile and would like to go quicker than 7.50 through the eighth.
The Pudding. The Proof.
Notice the 947rwhp number listed here. After dynoing just shy of 700hp on fuel and noticing a full bottle of nitrous on standby, David and friends introduced the engine to a healthy dose of N2O by way of ghetto fogging the turbocharger. On the squeeze, the truck put up just shy of 950hp, along with 1,631 lb-ft of torque.