JE Pistons Ultra Series GM Gen III/IV LS 4.065in Bore/4in Stroke Set of 8 Pistons

JE Pistons is well-known for making strong, reliable internal engine components, and their Ultra Series pistons are a prime example of that commitment. If you're building a high-performance GM Gen III or IV LS engine, especially one that will see boost or nitrous, these pistons are designed to handle the extreme cylinder pressures you'll encounter. They feature a 4.065-inch bore and are intended for a 4-inch stroke, making them a solid choice for many popular LS engine configurations.

What sets the Ultra Series apart is the level of detail and advanced features packed into each piston. They utilize JE's proprietary Aligned Grain Flow forging technology, which maximizes tensile strength to stand up to the intense forces in a performance engine. You'll also find a thermal barrier crown coating that reflects heat, helping to keep piston crown temperatures down and improve how efficiently the engine scavenges exhaust gases. For reduced friction and wear, the skirts are coated, which also helps quiet down operation, particularly when the engine is cold. These pistons also include lateral gas ports to help maintain a strong ring seal, even under high RPM and boost conditions, ensuring consistent power delivery.

This set includes eight pistons, each made from 2618 aluminum and featuring an inverted dome design with a volume of 14.90 cc, suitable for various compression ratio targets. They come with high-strength wrist pins manufactured by Trend Performance, designed specifically for the demands of power-adder builds. Every feature on these Ultra Series pistons is optimized for high-horsepower racing engines, and they are proudly made 100% in the USA. Please note that these pistons are not CARB approved and cannot be shipped to California.