Piston Kit D67.95 23630160Piston Kit (Cast BigBore)Cast BB Cast piston in original OE form for big bore cylinder All pistons are heat treated with a T 5 hardening and tempering cycle All piston skirts are coated with a high tech Molybdenum Disulphite coating for faster break in time and increased piston life Cast piston kits are gravity cast aluminum alloy (not forged) with 18% silicone content, which produces an extremely light but very strong piston Big Bore pistons increase