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

Starting with JE Pistons' proprietary Aligned Grain Flow Technology, these Ultra Series pistons are built for the serious demands of boosted or nitrous-fed GM Gen III/IV LS engines. This in-house forging process is designed to maximize tensile strength, giving you the confidence to push your engine to its limits under extreme cylinder pressures. Each piston in this set is precisely machined for a 4.010-inch bore and features a 3.622-inch stroke, with an inverted dome design that accommodates -6.40 cc of volume.

Beyond their core strength, these pistons are packed with custom-level features. A thermal barrier crown coating reflects heat, helping to keep crown temperatures down and improving exhaust gas scavenging. The skirts are coated to reduce friction and wear against cylinder walls, which also contributes to quieter operation, especially during cold starts. Lateral gas ports are integrated near the top compression ring to help maintain a solid ring seal, even when dealing with high RPMs and significant boost pressure. To ensure longevity and reduce heat and friction in the critical pin area, they include high-strength, thick-wall wrist pins from Trend Performance and feature optimized pin oiling.

This set includes eight pistons, eight high-strength wrist pins, and all the necessary lateral gas ports and thermal barrier coatings. Every component is made 100% in the USA, reflecting JE Pistons' commitment to quality and performance. Please note that these pistons are not CARB approved and cannot be shipped to California.