Wiseco K0421X85 Chevy LS 3.900 Stroker Forged Piston Kit 4.085 Bore -9cc Dish

The Wiseco K0421X85 is a Stroker Series forged piston kit engineered specifically for Chevrolet LS engines built around a 3.900-inch stroker crankshaft.

These pistons are optimized for the geometry of the 3.900-inch stroke rod angle, promoting smoother operation, reduced bore distortion, minimized crank and rod stress, and a more consistent ring seal throughout the RPM range. Designed for use with a 6.125-inch connecting rod and aftermarket rod bearings, the K0421X85 is intended for high-performance street/strip and race engine builds.

Key Features:

• ArmorGlide Skirt Coating — reduces friction, resists seizure, and enables quieter operation
• 2618 High-Strength Aluminum Alloy — forged construction for superior impact resistance under race conditions
• Fully machined crown features with precise -9cc dish profile for accurate compression ratio tuning
• Precision ring grooves with anti-detonation and pressure seal groove design
• 0.150-inch taper wall wrist pin with Spirolox retainers included
• Ringset included (P/N 4082GFX) matched for 4.085-inch bore
• Pin upgrade recommended for builds exceeding 700 HP (P/N S718)
• Engineered, forged, and machined in the USA at Wiseco's Mentor, Ohio facility

The K0421X85 piston kit is the ideal foundation for a high-displacement LS stroker build demanding proven forged durability and precise dimensional tolerances right out of the box.