These air cleaner kits are offered in two styles, the classic, which reflects many years of GM air cleaner styling, and the newer high-performance look. They are equipped with the CHEVROLET Emblem, and they are supplied with genuine GM (AC) air filter elements for maximum airflow. Both the tops and the bases have matching finishes, except carbon-style, and each kit is supplied with necessary mounting hardware. The classic air cleaner kits are supplied with special die-cast Bowtie center nuts, except P/N 141-906, also offered separately. The 14 inch air cleaner kits are supplied with 3 inch tall filter GM P/N 6421746 or AC P/N A212CW. For buyers wishing a taller 4.031 inch filter, purchase GM P/N 8997189 or AC P/N A697C. The bases of the 14 inch air cleaner kits are recessed for a low profile appearance, maximum performance and hood clearance. Technical Note: After installing a new air cleaner kit, always lower the hood slowly to confirm sufficient clearance visually. Minimum clearance of 3.75 inches is required from the top of the carburetor gasket area to the underside of the hood.