JE Pistons Ultra Series GM Gen III/IV LS 4.07in Bore/4in Stroke Set of 8 Pistons

When you're building a serious GM LS Gen III or IV 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 those demanding applications. You get the pistons themselves, ready for your build, along with high-strength wrist pins from Trend Performance, also made in the USA.

What sets these pistons apart is JE's proprietary Aligned Grain Flow forging technology, which gives them exceptional tensile strength. They also come with a thermal barrier crown coating that reflects heat back into the combustion chamber, helping to keep piston crown temperatures down and improving how exhaust gases are scavenged. On the sides, you'll find a skirt coating that works to reduce friction and wear on both the piston skirts and the cylinder walls, which also helps quiet things down, especially during a cold start. Plus, there are lateral gas ports designed to help maintain a strong ring seal, even when you're running high RPMs and significant boost.

These pistons are built for power, with every feature optimized for high-horsepower racing engines. They are made 100% in the USA, ensuring top-notch manufacturing. Keep in mind that these are not CARB approved and cannot be shipped to California. For a robust LS engine build that needs to perform under pressure, this set offers a well-built solution with advanced features.