Designed for cars with low hood clearance-Vettes, Camaros, etc. These brackets work great on most vehicles with a wide engine compartment -- Trucks, 50 - 60's cars, etc. These brackets bolt to the head and top water pump bolt holes. The alternator bracket will fit all 1969 and newer heads. The A.C. Compressor bracket fits all G.M. aluminum heads including the fast-burn aluminum heads and may be used on 1969 thru 1986 cast iron heads by drilling and tapping one hole for the upper mounting point.