Wiseco K422B125 Big Block Chevy Forged Piston Set 4.125 in. Bore Shelf Stock Kit

The Wiseco K422B125 is a shelf-stock forged piston set engineered for Chevrolet Big Block applications. Designed for a 4.125-inch bore (0.125-inch oversize) and matched to a 3.815-inch stroke, this kit provides an immediately available, off-the-shelf solution for engine builders who need proven Wiseco quality without custom lead times.

Wiseco's automotive shelf-stock piston kits are forged from high-strength aluminum alloy and feature a cam-and-barrel skirt profile for optimal piston-to-wall contact under real-world operating conditions. Each piston is machined with valve relief pockets and directionally marked on the crown for correct installation orientation.

Key Features:

• Application: Chevrolet Big Block (BBC) V8 engines
• Bore Size: 4.125 in. (0.125 in. / +0.125 oversize)
• Stroke: 3.815 in.
• Ring Groove Configuration: 1/16 in. – 1/16 in. – 3/16 in.
• Includes: Chrome moly wrist pins and Spirolox retaining rings
• Skirt Design: Cam-and-barrel profile for reduced friction and improved cylinder contact
• Shelf Stock availability: Ready-to-ship, no custom order wait time

Wiseco recommends a piston-to-wall clearance of 0.004 in., measured at 1.300 in. below the oil ring groove, 90 degrees from the wrist pin centerline. Always verify valve-to-piston clearance prior to final assembly, as variations in camshaft profile, deck height, and head milling can affect clearance requirements.

Manufactured in the USA, Wiseco shelf-stock piston kits deliver the same forged construction and dimensional precision as custom-order units, making the K422B125 an ideal choice for street performance, restoration, and mild racing Big Block Chevy builds.