Unleashing The Tune-Only ’23-’25 6.7L Power Stroke—645 HP At The Wheels

We’ve never seen tune-only horsepower numbers like this—and the figures being turned out by Proven Diesel’s ’23-’25 Super Duty test mules are some of the cleanest and most drivable yet. Strapped to the company’s in-house SF-849 SuperFlow dyno, its late-model Super Duty’s are going from 474 hp and 1,065 lb-ft of torque, stock, to 645 hp and 1,392 lb-ft at the wheels on tuning alone. Better yet, the trucks are maintaining tremendous street manners and factory-like drivability with 170+ hp and 320+ lb-ft gains on tap. Even though it doesn’t feel like that long ago, we are very far from the days of 500hp tune-only trucks. Welcome to the age of 650hp, 1,400 lb-ft beasts.

In The Dirt

36 Super Stock Trucks Invade Bowling Green, Ohio

The weekend of August 14-16, 2025 might’ve marked the largest group of Super Stock diesel trucks ever assembled in one location. The occasion? The 58th annual National Tractor Pulling Championships in Bowling Green, Ohio. First Place finishers included Zander Lee behind the wheel of “Kong,” and Dustin Beheler, who drove the “Diggin’ Deep” third-gen Cummins (a rare, 24-valve) to victory ahead of Shane Kellogg’s multi-ring-owning “Trump.” Jon Manns’ Haisley-powered, single turbo, ’77 Ford (“Crazy Ex”) earned an impressive, fourth place effort in session 1, while Scheid Diesel’s Brady Ingram turned in sixth and ninth place distances on the weekend. However, in the end the well-deserved ring winner was Todd Dugan and his “Angry Shine” Chevrolet, following a pair of strong, fifth and third place performances.

Drag ‘N Drive

WC Fab Runs Sick Michigan Miles

Wehrli Custom Fabrication’s short bed Silverado is doing exactly what it was built to do: compete in ride-and-drive style events with quickness and durability. Last week, the company’s compound turbo’d, LB7 Duramax-powered regular cab turned heads once again, this time along SICK The Magazine’s “Sick Michigan Miles.” During the week-long drag, drive, and cruise, driver Dustin West  kicked things off with a 6.78-second eighth-mile at Milan Dragway, shaved that ET down to a 6.75 at Northern Michigan Dragway, and then dropped it once again when the action reached The Ubly Dragway, this time to the tune of a 6.72 (at 106.67 mph). Dustin and WC Fab walked away with the event’s Quickest Diesel award.

At The ‘Strip

Turbos & Tailgates In Wilkesboro November 8^th

North Carolina’s Wilkesboro Dragway is under new ownership, ownership that seems to really like diesels, and they’re proving it by hosting a drag race and show ‘n shine on November 8th. The event’s heads-up, Diesel Truck Wars style racing classes include 7.70 and 6.70 Index, Outlaw (diesel only), and Singles Elite, with an ET Bracket category also being run. It’s the hope of all involved that Turbos & Tailgates will fill the gap left by the fall edition of Diesel Truck Wars no longer being held. And rumor has it that the event could expand to include a 3-day ride-and-drive in 2026…

Emissions

The Days Of DEF-Related Limp Mode May Be Over

Last week, the Environmental Protection Agency, under new Administrator Lee Zeldin, notified diesel truck manufacturers to eliminate DEF system-induced limp mode(s). Specifically, sudden and sharp power de-rating and 5-mph limp home penalties caused due to low DEF levels were ordered to be eliminated from OEM emissions and engine-related software. To be clear, power derating will continue to be part of diesel vehicle ownership, but not the kind that can strand you out in the cold and/or force a steep tow bill. Is this just the first step in the Trump Administration’s rollback of emissions regulations, or is it the only step the new administration will be taking? As always, time will tell, but this is great news for an industry that has been lobbying for these handicaps to go away for many many years.

Written by Mike McGlothlin