950-HP 7.3L Powerstroke Engine - Engine Builder Magazine

950-HP 7.3L Powerstroke Engine

If at first you don't succeed, try, try again. A few broken rocker arms and a bent connecting rod didn't stop David Keyser. In fact, he used it as motivation to build this 7.3L Powerstroke to handle even more horsepower and punishment. Check it out!

Diesel of the Week is presented by

With how widespread and diverse the engine building community is, we find people all over the planet with interesting builds. Social media, motorsports events, word of mouth, you name it – we get in contact with builders no matter what the medium.

David Keyser first reached out to us about a week ago on Facebook Messenger, asking where he could enter to be in Diesel of the Week. What some of our readers may not know is that it’s as easy as that! There is no entering process for our Engine of the Week or Diesel of the Week series; if you think you have an interesting build that our audience would like to see, simply send us a direct message on our social media channels (Instagram, Facebook or Twitter) or email our Editor Greg Jones at [email protected].

When David Keyser messaged us, he outlined his 7.3L Powerstroke that makes nearly 1,000 horsepower, so naturally we wanted to know more. Keyser works as an over-the-road heavy equipment technician and on the side, he started GapTrain Performance, a small diesel performance and off-road business. On first sight, we were curious to know if David was related to Travis Keyser, another engine builder we spoke with early this year. Interestingly, their shared name is simply a coincidence.

“No, I’m not related to him…. and it’s an uncommon name,” Keyser says. “The funny thing is we raced together at the same event one day. They called out Keyser and I spoke up thinking they made a mistake.”

The one thing both Keyser’s do share is a love for Powerstrokes. Travis’ 6.0L was a sight to see, and now David’s 7.3L is our next fixation.

David first started playing in the diesel world around 2013, when he purchased a garage kept, bone-stock ‘97 F-250. A few years in, he decided to take the build more seriously and improve the factory rated 225 horsepower. At that point around 2016, Keyser was working on diesel trucks every day in a local shop gaining valuable experience and insight into how he could improve his truck’s performance.

“The original goal was to just put in a small set of injectors, a drop-in turbo, and then do a mild built transmission,” he says. “The setup was a 180/100 injectors, a T500 high-pressure oil pump, a mild built transmission, and then we left the stock turbo in it. Well, I wanted more, so we put an S369 on it along with some bigger injectors, 275/200 I believe.”

Unfortunately, Keyser said that on the first trial, the setup broke six rocker arms, a rocker pedestal, and bent a connecting rod. At that point, he had two options – reduce the power output or double down and build an engine that could hold the power it made. He chose the latter.

The new engine belts out nearly double the horsepower and is far and away more reliable. Keyser doesn’t daily drive the truck anymore, but still drives it often. Just a few weeks ago, he drove it seven hours straight to Virginia Beach and back, proving that it can throw down on the dragstrip and party on the street.

“I got 350/200 injectors from Full Force Diesel Performance, a Swamps Motorsport Gen3 high-pressure oil pump and a big, Forced Inductions S476 turbo that works pretty well with the Irate Diesel T4 turbo mount. There’s also a CSF intercooler for a 6.0L that I swapped into it and that manages the 55 psi of boost.”

On the bottom end, the engine features an Irate girdle, Manley connecting rods, ARP main studs, and fly-cut standard bore pistons. A set of ported cylinder heads from Crutchfield Machine with 165-lb. valve springs and ARP studs anchoring them to the block sit above o-ringed head gaskets.

“It was nice because I didn’t really have to get anything machined,” Keyser says. “I was able to use stock size pistons, so really the only thing I had done was getting the crank balanced at my local machine shop.”

Right now, Keyser’s 7.3L Powerstroke is capable of around 950 horsepower and 1,630 lb.-ft. of torque, which has gotten him a 7.11 second pass at 99.8 mph in the 1/8th mile. While he admits that his 60 foot time is “pretty terrible,” he’s already working on improvements to make his F-250 faster than it is now.

Diesel of the Week is sponsored by AMSOIL. If you have an engine you’d like to highlight in this series, please email Engine Builder Editor Greg Jones at [email protected].

You May Also Like

Turbocharged 7.3L Powerstroke Engine

Every year, there’s hundreds of diesel trucks at the Ultimate Callout Challenge. As expected, most feature 6.7L Cummins engines, but that’s what makes seeing a Powerstroke build that much more special – let alone a 7.3L. We were able to find one built and owned by Corey Hurtts of CNC Fabrication. Check it out!

Corey Hurtts’ journey in the diesel world started with a humble service truck powered by a 7.3L Powerstroke engine – little did he know this would be the spark that ignited his passion for welding and fabrication. As he bought and worked on his own 7.3L truck later in life, Corey's interest in diesel engines grew, and he eventually delved into manufacturing and building performance engines.

Compound-Turbo 6.0L Powerstroke Engine

Did we expect to see a 1962 Ford Country Squire at a huge diesel racing competition? No. Were we inevitably hyped up when we saw one at the 2023 Ultimate Callout Challenge? Hell yes. This one has a beefy 6.0L Powerstroke swapped under the hood making it a kickass combo worthy of our Diesel of the Week!

6.0L Powerstroke Swapped Mustang

Tyler Hewett’s clothing brand “Anti Cummins Swap Club” will tell you all you need to know about him… so will his 6.0L Powerstroke swapped Mustang. We got to see it up close at the 2023 Ultimate Callout Challenge. Check it out!

Compound-Turbo 5.9L Cummins

Cancer Sucks! This Chevy S10 from the guys over at Stainless Diesel not only packs a punch with it’s compound-turbocharged 5.9L Cummins, but promotes the awareness and fight against the deadly disease.

Turbocharged 6.0L Powerstroke Engine

This 6.0L Powerstroke is the first race-build from owner Connor Wagner and the team at Wagner Diesel Solutions. They ran it this year at the Ultimate Callout Challenge. Check it out!

Other Posts

632 cid Big Block Chevy Nitrous Engine

With a storied race history of his own, Sandy Wilkins has taken his passion for cars and engines and turned it into his life. From race teams to Roush Yates Performance to opening Wilkins Racing Engines, he knows how to build high-horsepower engines like this 632 cubic inch big block Chevy nitrous engine for No Prep drag racing. Check it out!

Wilkins Racing Engines’ 632 cid Big Block Chevy Nitrous Engine

Sandy Wilkins of Wilkins Racing Engines recently allowed us to visit his engine and machine shop in Mooresville, NC. We were thoroughly impressed by how clean and organized his shop was and the caliber of the engines his shop churns out. We got the full details of this big block Chevy nitrous engine he built

Cancer Sucks S10 with a Compound Turbo 5.9L Cummins Engine

It’s hard to miss Stainless Diesel’s #CancerSucks S10, which features a compound turbo 5.9L Cummins engine. During the 2023 Ultimate Callout Challenge, we caught up with Steve O’Neal to get the details of this special truck and it’s Cummins powerplant for our Diesel of the Week. Related Articles – Harrell Engine & Dyno Shop Tour

448 cid Billet LS Engine

Pete Harrell of Harrell Engine & Dyno is real good at doin’ stuff, like building turbocharged and forced induction high-powered engines such as this 448 cid billet LS engine for Limited Drag Radial. Check out what went into this 2,500+ HP engine!