ATK High Performance Engines Engine Short Block

ATK High Performance Engine Short Blocks: The Foundation of a Serious Build

When a build calls for a rock-solid foundation, the ATK High Performance Engines short block lineup delivers a level of engineering and component quality that serious builders demand. Rather than handing you a bare, bone-stock core, ATK assembles each engine short block with premium, performance-grade internals — so the hard work of choosing and matching rotating assembly components is already done for you.

What Sets ATK Short Blocks Apart

ATK High Performance was established in 2007 in Grand Prairie, Texas, and has since grown into one of the largest performance engine shops in the country. The company is led by Mark Johnson, who began his career with renowned race engine builder Reher & Morrison, where he participated in development programs for major sponsors including GM, NASCAR, and Pro-Stock engine builds. That racing pedigree is baked directly into every short block ATK assembles.

ATK engines are reverse engineered to identify any shortcomings in OEM designs and improve on them with superior components. The result is a short block that doesn't just replace what came out of your vehicle — it upgrades it. ATK was the first to offer a "new car" style warranty with its engines — an exclusive 24-month/unlimited-mile warranty on every engine.

Short Block Families and Configurations

ATK's short block catalog spans some of the most popular American performance platforms. Options include new short blocks in displacements such as 377 CI with cast-iron blocks, 4.0" bore, forged I-beam or H-beam rods, and forged aluminum flat-top pistons with internal balance for Chevy small-block applications. On the modern LS side, offerings include LM7 383 short blocks featuring forged cranks, forged pistons, I-beam rods, and 6-bolt mains, as well as LS Gen IV 408 stroker assemblies with internally balanced internals, 24-tooth reluctor wheels, and dish pistons.

For Gen V enthusiasts, ATK also produces short block assemblies for the LT1/LT4 platform in both 6.2L/376 and 6.8L/416 displacements, with forged pistons, two valve relief, and 58-tooth reluctor compatibility. Ford fans aren't left out either — big block Ford 385/460 short block assemblies are part of the lineup, featuring a 2-piece main seal design.

At the top of the range sits the ATK Elite Series. ATK's Elite Series LS Short Blocks are positioned as a step above the rest , targeting builders chasing extreme power numbers. ATK has been documented setting up Calico-coated bearings in Dart Machinery LS SHP blocks for 1,800 HP-rated short block builds intended for custom turbo applications.

Who Are ATK Short Blocks For?

ATK provides high-performance engines for muscle cars, trucks, daily drivers, and even boats, with designs aimed at making engine swaps or hot rod builds easier. Whether you're refreshing a tired small-block or building a stroker for the strip, an ATK short block gives you a proven, warrantied rotating assembly that eliminates the guesswork and machine-shop hours of a ground-up build.