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 some of the strongest pistons you can get off the shelf, and their Ultra Series is a prime example. If you're building a GM Gen III or IV LS engine that's going to see serious boost or nitrous, these are the pistons you want in your corner. They're designed from the ground up to handle the extreme cylinder pressures that come with power-adder builds, ensuring your engine can take the punishment.

What sets these Ultra Series pistons apart is JE's proprietary Aligned Grain Flow forging technology. This in-house process maximizes the tensile strength of the aluminum, giving them the backbone to withstand the immense forces at play in a high-horsepower engine. On top of that, they come loaded with custom-level features usually found only in fully bespoke builds. You get a thermal barrier crown coating that reflects heat, helping to keep temperatures down and improve how efficiently the engine scavenges exhaust gases. The included Trend Performance wrist pins are thick-walled and built for the demands of these high-performance applications. Plus, there's a skirt coating to reduce friction and noise, especially noticeable during cold starts, and lateral gas ports to help maintain a solid ring seal even under high boost and RPM.

These pistons are optimized for power, with every feature working together to support high-horsepower racing engines. They are made 100% in the USA, and while they are not CARB approved and cannot be shipped to California, they represent a solid option for serious engine builds elsewhere. This set includes eight pistons, each with a 4.065-inch bore and designed for a 4-inch stroke, ready to be the foundation of your next high-performance LS project.