Heater CORE: 63-68 GM Various w/o Factory ACThis is the core for the GM U. S. Cars without FACTORY AC and that never had factory AC as shown below.. there may be other applications also. Most are now ALLOY not cooper. 63 68 Chevy Impala, Belair but larger then the ones often found on RHD Holden built cars. 65 68 El Camino, Chevelle, Monte Carlo, Malibu (NOT FOR U. SA PONTIAC big cars Like Bonneville or Catalina etc.. not.. NOT BUICK SKYLARK 1964 1967 BUICK SPECIAL 1964 1967 CHEVROLET BEL AIR