JE PISTONS Piston Kit - 4.250" - M8 391731

High-boost and high-RPM applications demand pistons engineered to withstand extreme combustion pressures and thermal stress—stock units simply won't survive. The JE Piston Kit 4.250" delivers the strength-to-weight ratio and reliability required for forced induction engines, whether you're building a turbocharged street machine or a dedicated race engine. With advanced grain flow forging and multiple durability enhancements, these pistons are designed to maintain consistent ring seal and structural integrity across repeated power cycles.

• Advanced grain flow forging
• Ceramic crown coating
• Internal/external bracing
• 3D undercrown milling
• Reduced overall weight
• Lateral gas ports
• Accumulator groove design
• Skirt friction coating
• High-RPM ring seal
• Boost-rated construction
• Superior tensile strength
• Extended piston lifespan
• Part number: 391731
• Bore diameter: 4.250"
• M8 platform specific