WISECO K398X7 GM LS-Series Forged Flat-Top Piston and Ring Kit, 4.070 in Bore

Build a reliable, high-performance GM LS-Series engine with the WISECO K398X7 forged piston and ring kit. Designed for LS applications with a standard stroke, this set combines durable forged construction with a flat-top crown profile and a -3.20 cc volume to support precise compression-ratio planning. The 4.070-inch bore is suited to properly prepared LS engine blocks and provides a dependable foundation for street, performance, and competition builds.
The WISECO K398X7 features a 1.304-inch compression height and a 1.2 x 1.2 x 3.0 mm ring-groove configuration. Its included piston ring package is engineered to complement the piston design, helping promote consistent sealing, efficient combustion, and dependable oil control when installed with the correct clearances and assembly procedures. As with any performance rotating assembly component, professional measurement and tuning are recommended before final installation.
This GM LS-Series piston and ring kit is a practical choice for engine builders seeking forged strength and a straightforward flat-top configuration. The kit format simplifies component selection while maintaining the fitment details required for compatible LS builds. Confirm bore preparation, crankshaft stroke, connecting-rod specifications, piston-to-valve clearance, compression ratio, and ring-gap requirements before installation. The WISECO brand and K398X7 part number provide clear identification for engine planning, parts matching, and future service needs.

Features:

• Brand: WISECO

• Part Number: K398X7

• Application: GM LS-Series engines

• Construction: Forged piston design

• Piston Style: Flat-top crown

• Bore Size: 4.070 inches

• Stroke Configuration: Standard stroke

• Compression Height: 1.304 inches

• Ring Grooves: 1.2 x 1.2 x 3.0 mm

• Piston Volume: Minus 3.20 cc

• Kit Contents: Piston and ring set