Jack Brooks’ Twin-Turbo 540 Big Block Chevy Engine is a Gritty Drag-and-Drive Powerhouse - Engine Builder Magazine

Jun 06, 2025

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At Sick Week 2025, which began and ended at South Georgia Motorsports Park, the staging lanes are filled with high-powered hot rods. Sometimes, it’s the cars you least expect to surprise you that actually surpass expectations. Take Jack Brooks’ Chevy II. Covered in natural patina, the outside of the car was nothing spectacular, but under the hood was a twin-turbo 540 cubic inch big block Chevrolet. It stood out, not just for its twin 88mm turbos peeking through the engine bay, but for the story behind the build.

Jack’s car didn’t start out as a high-horsepower drag-and-drive beast. About five or six years ago, the Chevy II was a project in its early stages – powered by a single-turbo LS combo that ran solid 8.50s. It was a respectable streetcar. But over time, as the drag-and-drive bug bit deeper, Jack’s goals shifted. Horsepower, reliability, and a do-it-yourself spirit became the new blueprint.

Today, the Chevy II is propelled by a low-compression, mild-cammed 540 cid big block Chevy with billet internals and twin HPT 88/103 turbos supplying the boost. Jack describes the engine as “run-of-the-mill,” but that undersells a setup that puts out somewhere between 2,000 and 2,500 horsepower – and it hasn’t even been pushed to its full potential yet. Thus far, the car has only seen 25 psi of boost, but Jack admits this combo is just getting started.

“I don’t think these things get happy until after 25 pounds,” Brooks says of the turbo setup. “Hopefully, we can see what it really wants this week.”

Supporting the big block Chevy engine are components from some of the best in the business. The rotating assembly includes MGP aluminum rods and JE pistons, while camshaft duties are handled by an Isky Racing Cams unit. The choice of HPT turbos reflects Jack’s desire to support brands that are embedded in the drag-and-drive scene – companies that understand the abuse and demands of this brutal, multi-day format.

The car runs in the Unlimited Iron class, where the only major rule is a 3,000-lb. minimum weight. Otherwise, it’s wide open – exactly the type of class for a home-built car that punches well above its weight. But for Jack, this year is about more than competition.

“We didn’t make it past Day Zero last year,” he says. “This time, the goal is just to make it through the week, get good data, and learn more about the combo. If we can get some clean A-to-B passes, whether that’s a 7.50 or an 8.50, that’s a win.”

There’s no mistaking the Chevy II in the lanes. The weathered patina is completely authentic – not sprayed on, not faux. “What you see is exactly how I bought it,” Jack says. “It hasn’t been touched.” The finish is part of the story. The car was largely built from scrap parts laying around the fabrication shop where Jack works part-time, plus secondhand pieces, and whatever he could scrounge while still getting the job done right.

More than anything, the car represents a journey of learning. Jack taught himself how to weld, bend tube and fabricate on this project. He didn’t start out as a pro builder – this was his classroom. Over the years, he and his friends have logged countless late nights solving problems, fixing mistakes and figuring out how to make the car faster, safer and more consistent.

“I’m just really proud of what we’ve done,” he says. “I’ve had people around me that helped me push through when things got tough – and when I made mistakes, they were there to help me learn and fix them.”

It’s that spirit – a blend of grit, resourcefulness and horsepower – that makes Jack Brooks’ Chevy II and its twin-turbo big block a perfect fit for Sick Week. It’s not just about building something fast. It’s about building something real.

Jack’s week in the Ultimate Iron class unfortunately ended early, but he did get past day zero this year. He recorded ETs of 9.50 at 170 mph, 15.28 at 93 mph and 8.24 at 174 mph, before having to abandon. While Jack is still working out all the kinks, and his license limits him to 7.50 ETs or slower, he says the Chevy has 6-second potential. We’re excited to see that come to fruition soon.

Engine of the Week is sponsored by PennGrade1 and Elring – Das Original. If you have an engine you’d like to highlight in this series, please email Engine Builder Editor Greg Jones at [email protected].