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djprecisionmachine.com
New product release • October 1, 2026
New From D&J LML Long Blocks
Two purpose-built 2011–2016 6.6L LML Duramax long blocks. Precision-machined, assembled, and tested in-house by D&J Precision Machine.
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THE D&J IDENTITY
Headquartered in the heart of Ohio, D&J Precision Machine stands as a powerhouse in the diesel performance industry, tracing its roots from CEO Drew Pumphrey’s visionary intersection of service industry expertise and fabrication ingenuity. D&J’s commitment to innovation and excellence is evident in its state-of-the-art facility, where precision machinery and a meticulous approach to craftsmanship result in components that transcend mere construction, embodying the art of engineering. More than a name, D&J Precision Machine is a promise of excellence, innovation, and a collaborative journey into the forefront of the industry.
Customer Rides
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When it comes to building a high horsepower diesel, every single detail counts. Whether you're hitting the drag strip, hooked up to...
Speed & Salt: How Tim Boyle Brought Record Breaking Diesel Power to the Bonneville Salt Flats
There’s a legendary pull to the Bonneville Salt Flats, a shimmering, endless white expanse where land speed records are broken and horsepower...
Austin Doidge & The 2,500 HP Firepunk Anteater
When Ohio native Austin Doidge rolled into Rudy’s for the opening event of the season, the goal wasn't just to make passes,...
Let customers speak for us
Great communication! Have questions just call real person answers and great help. Got head studs and stage 1 head. Great work guys!
Brandon Gonzalez
Very high quality product install is straight forward and easy every thing fits as it should!
Jason Maddox
very high quality long block.
Danny Witt
So far, everything’s been great. I highly recommend this company. They ship quick they deliver their products on time and exactly what you ordered.
Bob Worthington
Great kit, comes with everything you need to install the valve cover and remove the factory lines going into the side of the valve cover. Just wish it came with some stickers lol
Dom
Really happy with my new billet valve cover
Frankie Almodova
Easy install. Some instructions would be helpful… semms good quality. Needs a good wipe inside from machining debris other then that looks good after a week.
Ruben
Austin was great to talk to and get me the exact parts I needed!
Ethan Lubbehusen
Works great
Randy Carlisle
10/10 recommendation, will fix oil leaks
Anonymous
Worked no isssue
Pat
Perfect
Pat
Good place to buy from
Anonymous
Awesome product!
Awesome customer service!
Gerald Goss
Very knowledgeable and friendly, helpful staff
Brian Pelter
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