KB Performance Hypereutectic Piston for 4.25 Stroke 3.498" Standard 8.3:1

KB Hypereutectic alloy pistons are cast with a 16% high silicon content that has very high thermal barrier properties along with a low thermal expansion rate, allowing tight piston to cylinder wall clearances. This makes them ideal for air-cooled engines, offering optimal ring seal, quieter engine running and reduced wear. Hypereutectics are best suited for stock or mild compression ratios up to 10.5:1 running on pump fuel.

• Manufactured from high-strength, T-5, heat-treated, 390 hypereutectic aluminum alloy
• Allow a tighter fit and longer piston and ring life
• Diamond-machined pistons are held to plus or minus one gram weight and less than one-half-thousandth-inch (.0005") tolerances from piston to piston
• Each kit contains two pistons, pins, spiral-lock pin clips and Hastings moly rings