Race Pro Radiators - 28 x 19 x 3 1/8 GM Triple Pass CORE HAS 2 ROWS OF 1" TUBES; MACHINED BILLET ALUMINUM SAE COMPLIANT FILLER NECK; TRIPLE PASS RADIATORS PASS COOLANT THROUGH THE RADIATOR 3 TIMES BEFORE EXITING AND REQUIRE GREATER FLOW THAN STANDARD RADIATORS; IT IS RECOMMENDED THAT YOU USE 1 TO 1 PULLEYS, A HIGH VOLUME WATER PUMP, AND USE NO RESTRICTORS IN THE SYSTEM;