This big bore cylinder and piston kit contains S&S 4-1/8" bore cylinders and forged flat topped pistons, rings, wrist pins, head and base gaskets. The cylinders are machined with the stock bolt pattern and are intended for use in stock crankcases of 2007-'17 big twin except 2017 touring engines. The stock 4-3/8" stroke and 4-1/8" bore result in a 117' displacement. Cylinder finish is a durable wrinkle black powder coat. This cylinder kit may be used with stock or S&S cylinder heads with stock bolt pattern. For best performance, appropriate camshafts, performance air cleaner, performance exhaust and fuel system tuning are required. Although not mandatory, we recommend adding an oil cooler to bikes ridden in warmer climates.