Wiseco K0421XS Chevy LS 3.900 Stroker Forged Piston Kit 4.000 Bore .927 Pin

The Wiseco K0421XS is a professional-grade forged piston kit engineered specifically for Chevrolet LS stroker builds running a 3.900-inch stroke. The kit includes pistons, rings, and wrist pins — everything needed for a complete stroker assembly.

These pistons are geometrically optimized for the rod angle produced by a 3.900-inch stroke, promoting smoother operation, reduced bore distortion, and lower stress on the crankshaft and connecting rods — while maintaining a consistent ring seal throughout the RPM range.

Key Features:

• ArmorGlide Skirt Coating — A permanent dry-film lubricant that reduces friction, resists seizure, and allows tighter piston-to-wall fitment for improved performance and quieter operation
• 2618 High-Strength Forged Aluminum — Manufactured in the USA at Wiseco's Mentor, Ohio facility using 2618 alloy, which compresses material molecules during forging for superior tensile strength and impact resistance
• Fully Machined Crown — Precision-machined -9cc dish crown for accurate and consistent combustion chamber volume
• Precision Ring Grooves — Anti-detonation groove and pressure seal groove features improve ring seal, reduce piston rock noise, and prevent carbon buildup on the ring land
• Forced Pin Oiling — Ensures effective lubrication of the wrist pin under extreme load conditions
• Reluctor Ring Clearance — Pin boss design accommodates the reluctor ring on stroker crankshafts without requiring notching

Compatible with a 6.125-inch connecting rod length. Wiseco's Professional Series pistons are built to withstand heavy- to severe-duty race applications, and are the choice of serious engine builders and racers demanding the highest level of quality and performance from their LS stroker build.