JE Pistons Ultra Series GM Gen III/IV LS 4.135in Bore/4in Stroke Set of 8 Pistons

If you're building a high-horsepower GM Gen III or IV LS engine, especially one that will see boost or nitrous, you need pistons that can handle the extreme cylinder pressures. JE Pistons' Ultra Series are designed specifically for these demanding applications. They're not just strong; they're packed with features usually found only in custom piston sets, all ready to go right out of the box.

What sets these pistons apart is JE's proprietary Aligned Grain Flow forging technology. This in-house process maximizes the material's tensile strength, giving these pistons the backbone needed to withstand the intense forces in a power-adder engine. 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 keep piston crown temperatures down and can even improve how efficiently exhaust gases are scavenged. For reduced friction and wear on the skirts and cylinder walls, a special skirt coating is applied, which also helps quiet down operation, especially when the engine is cold. Plus, they've included lateral gas ports to help maintain a solid seal on the top compression ring, even at high RPMs and under heavy boost.

These Ultra Series pistons are made from 2618 aluminum and feature a flat-top design with a -5.00cc dish, suitable for a 4.135-inch bore and a 4-inch stroke. They come with high-strength, thick-wall wrist pins manufactured by Trend Performance, designed to handle the rigors of high-performance builds. Every feature on these 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.