Mac's brings you the best aluminum radiators in both quality and the latest technology. The two row, one inch tube design allows added cooling not found in standard single row radiators. Included, at no extra cost, is the billet aluminum filler neck. Aluminum radiators are typically 50-60% lighter than the average copper/brass unit. These fine, hand crafted radiators are made in the USA. Other features include vacuum brazed cores with no epoxy . The end tanks are fully welded by hand for the custom finish. Many leading custom radiators are constructed this very way. GM radiators use a top drivers side inlet and bottom passenger side outlet.