JE Pistons Ultra Series GM Gen III/IV LS 4.065in Bore/3.622in Stroke Set of 8 Pistons

If you're building a high-horsepower GM Gen III or IV LS engine, especially one that's going to see boost or nitrous, you need pistons that can handle the extreme cylinder pressures. These Ultra Series pistons from JE Pistons are designed specifically for those demanding applications. They feature JE's proprietary Aligned Grain Flow forging technology, which maximizes tensile strength to stand up to the stresses of serious power adder builds. Every aspect of these pistons is geared towards performance, from the thermal barrier crown coating that reflects heat back into the combustion chamber, to the friction-reducing skirt coating and lateral gas ports that help maintain ring seal even under high boost.

Beyond the core strength, JE has included custom-level features you'd typically only find in fully bespoke racing pistons. The thermal barrier crown coating not only helps manage heat but also improves exhaust gas scavenging. The skirt coating reduces friction and wear on both the piston and cylinder walls, which also helps quiet down operation, especially when the engine is cold. You'll also find optimized pin oiling features to ensure the wrist pins and bores stay well-lubricated, reducing heat and wear. The included high-strength wrist pins are made by Trend Performance and are built to handle the rigors of high-performance engines. These pistons are designed to maintain a solid ring seal, even at high RPMs and under significant boost, thanks to the lateral gas ports.

These pistons are made 100% in the USA, reflecting JE Pistons' commitment to quality manufacturing. They have a 4.065-inch bore and are designed for a 3.622-inch stroke, with an inverted dome that has a -8.50cc volume, making them suitable for various compression ratio targets depending on your cylinder heads. Keep in mind that these are not CARB approved and cannot be shipped to California. If you're aiming for serious power with your LS engine, these Ultra Series pistons are a well-built foundation.