JE Pistons Ultra Series GM Gen III/IV LS 4.01in Bore/3.622in Stroke Set of 8 Pistons

If you're building a high-horsepower GM LS Gen III or IV engine, especially one intended for boost or nitrous, the JE Pistons Ultra Series is a solid choice for your internal rotating assembly. These aren't just any pistons; they're built from the ground up with features typically found only in custom applications, designed to handle the extreme cylinder pressures that come with serious power adders.

What sets the Ultra Series apart is JE's proprietary Aligned Grain Flow forging technology. This process maximizes the tensile strength of the aluminum, giving these pistons the backbone needed to withstand the immense forces in a boosted or nitrous-fed V8. You'll also find 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 efficiently exhaust gases are scavenged. For reduced friction and wear on the cylinder walls and piston skirts, a skirt coating is applied, which also helps quiet down operation, especially when the engine is cold. To ensure proper lubrication in demanding conditions, these pistons feature optimized pin oiling, and lateral gas ports are included to help maintain a strong ring seal even at high RPMs and under significant boost.

This set includes high-strength wrist pins from Trend Performance, known for their durability in high-performance builds. Every feature on these Ultra Series pistons is optimized for high-horsepower racing engines, and they are made 100% in the USA. Please note that this kit is not CARB approved and cannot be shipped to California.