Manley Chevrolet Small Block Piston Set - 4.040in Bore 1.125in CH, 11.00 CC2618 Alloy Forgings: We use domestic 2618 alloy forgings, ensuring superior strength and performance. Chrome Moly Wrist Pins: Premium Chrome Moly wrist pins come standard with our Standard Series Pistons. For select SKUs, we offer wrist pin upgrades to 9310 and Turbo Tuff DLC alloys, providing additional durability. Exacting Ring Lands and Grooves: We adhere to strict standards for piston ring lands and grooves, resulting in enhanced ring seal and