Afco Double Pass All Aluminum Racing Radiators are designed to solve severe overheating problems on race car applications. Their unique design makes the coolant flow across the core and then back providing all the cooling capacity possible doubling the efficiency of the core size. High capacity 1” aluminum tubes for greater cooling capacity. Billet Aluminum filler neck for durability. Comes standard with 1-1/2” inlet and 1-3/4” outlet. On double pass radiators the inlet and outlet are on the same side.