For those readers who feel you have to “delete” your diesel truck to make big horsepower, I give Kory Willis and PPEI Tuning as proof that is not true. Kory has been tuning diesel trucks for a long time, and specializes in emissions-intact tunes that can make your Power Stroke, Duramax, or Cummins engine run better than you ever imagined.

Take for instance this 2021 Ford Super Duty. It’s a stock-looking truck that hides a monster under the hood. With a PPEI tune and just a 64-millimeter turbo from Ryan’s Diesel Service, the 6.7-liter Power Stroke now lays down an impressive 632 horsepower and 1,230 pound-feet of torque on the dyno. Keep in mind, that this Power Stroke retains the EGR, DPF, and everything else emissions related.

Those are serious gains of horsepower and torque when you factor in that the truck is rated from the factory with 475 horsepower and 1,050 lb-ft of torque. “Sure, we can send it to the moon and make an awesome marketing number…. but this truck was 448 to the tire stock,” says Kory.

It looks completely stock, and it is except for a turbo upgrade and PPEI custom tuning.

I do have to tell you, this tune and turbo combo isn’t CARB-ready just yet. It still requires a CARB EO number, which takes a lot of testing. However, PPEI is confident it will pass these tests as they have kept emissions within 10 percent of the OEM’s standards. What’s more, all that extra power hasn’t affected NOx output, so the truck should not be chugging any more go-juice than it did when it left the factory.

“448 horsepower to 632 horsepower is no joke,” Kory quips. “This is what you can expect and replicate anytime anywhere with the same mods and our tuning.”

Although Kory made it look easy, PPEI didn’t hit the 632-horsepower number on its first try. There were several pulls made to adjust the tuning to a point that satisfied Kory so the truck would remain reliable while it makes the number. Kory even feels it could make even more power if he wasn’t trying to stay close to the stock emissions output. With this truck, Kory has proven that big power numbers can be had while emissions stay intact.

What PPEI and Ryan’s Diesel Service have accomplished is setting a bar that all tuners should strive to achieve. A substantial increase of power, all while keeping the truck owner — and the EPA happy. This is proof positive that it can be done.