Federal Mogul WH856CP40 GM LS Cast Piston 3.820 Bore Dished +0.040 Oversize

The Federal Mogul WH856CP40 is a cast aluminum replacement piston designed for GM LS-series engines, featuring a dished crown profile and a +0.040" oversize bore diameter of approximately 3.820". Sold as a single piston, it is ideal for replacing individual pistons during engine rebuilds or as part of a custom assembly order.

Manufactured under Federal Mogul's trusted Speed Pro / Sealed Power piston line, this cast piston delivers OE-quality fitment and durability for street and mild performance applications. The dished crown design is engineered to work with the combustion chamber geometry of LS-platform V8 engines, helping maintain proper compression ratios in standard and lightly modified builds.

Key Features:

• Application: GM LS-series V8 engines
• Bore Size: 3.820" (+0.040" oversize)
• Crown Style: Dished
• Construction: Cast aluminum
• Quantity: Single piston (1 piece)
• Ring Groove Dimensions: 5/64" x 5/64" x 3/16" (standard LS ring pack)
• Manufacturer: Federal Mogul / Speed Pro / Sealed Power

This piston is part of the H856CP family, which is the standard GM LS dished cast piston set line. The WH856CP40 is the single-unit, +0.040" oversize variant — suitable for engine blocks that have been bored 0.040" over standard. Piston rings are sold separately.