1970 Pontiac GTO LeMans Radiator Fan Shroud. 3 or 4 core This fan shroud is identical to the original is has the side protection flap on the drive side that wraps the side of the radiator between the battery. It was there so if you were working on the car battery you could not burn yourself on the side of the radiator. This Flap was discontinued some time in 1970. The only difference between 3 and 4 core is the pads that sit on the ends of the radiator. There is no difference in the shroud.