Forged Piston Set, 4.0L, -10cc Dish, 3.875-Inch Bore

The DSS Racing 6650-3875 is a set of forged pistons engineered for AMC/Jeep 6-cylinder 4.0L engines. These pistons are forged from 2618 alloy, known for its strength and durability under high stress, making them suitable for boosted applications like superchargers, turbochargers, or nitrous oxide systems. Key specifications include a 3.875-inch cylinder bore size, a 1.592-inch compression height, and a 0.931-inch pin diameter. The pistons feature a -10cc dish top design with no valve reliefs, which affects the compression ratio. Depending on the cylinder head combustion chamber size (52cc, 55cc, or 58cc), the approximate compression ratio ranges from 10.53:1 down to 9.77:1. This specific piston set has a ring groove width of 1.2/1.2/3MM. It's important to note that parts manufactured before June 15th, 2026, featured older ring groove dimensions of 1.5-1.5-4MM. The connecting rod length is 6.125 inches, and the crankshaft stroke is 3.440 inches. DSS Racing highlights that these pistons are forged and machined in the USA, emphasizing quality and domestic manufacturing. They are available with options for either no rings or with DSS Racing rings included.