interstate driving = overheating?

[Pdale]

My dad had this problem with his El Camino when he put the lumina front end on it. It wouldn't get enough air at highway speed. Even with duel high flow fans. The front end deflected the air over and under the radiator. He was able to get a deflector that goes under the car right behind the radiator and it deflects the air up at the radiator. So maybe not enough flow through the radiator?