JE Pistons Ultra Series GM Gen III/IV LS 4.01in Bore/4in Stroke Set of 8 Pistons

When you're building a serious GM Gen III/IV LS engine, especially one that's going to see boost or nitrous, you need pistons that can handle the extreme cylinder pressures. This set of eight Ultra Series pistons from JE Pistons is designed precisely for that kind of demanding application. They feature JE's proprietary Aligned Grain Flow forging technology, which is an in-house process that maximizes tensile strength to stand up to the stresses of high-performance engine builds.

What you get in this kit are pistons with custom-level features you'd typically only find in a full custom build. They include a thermal barrier crown coating, which is a ceramic-based material that reflects heat back into the combustion chamber. This helps reduce piston crown temperatures and can improve how the exhaust gases are scavenged. The skirts are coated to reduce friction and wear on both the piston and cylinder walls, which also helps quiet down the engine, especially during cold starts. You'll also find lateral gas ports, which are crucial for maintaining a strong ring seal even at high RPMs and under significant boost. Plus, they come with high-strength, thick-wall wrist pins from Trend Performance, designed for the rigors of power-adder builds, and feature optimized pin oiling to keep everything well-lubricated.

These pistons are made 100% in the USA and are specifically optimized for high-horsepower racing engines. 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, this set is built to get you there.