Gasoline-powered dirt oval track cars require more water pump and fan speed than a comparable pavement car. This is due to the lower engine speeds in the corners, and the increased possibility of clogged grille screens. A mechanical fan with a proper shroud is a necessity for these applications.
Nearly all street rods are equipped with an upright radiator that positions the radiator cap on the pressure side of the system, thus subjecting the cap to the pressure generated by the water pump. The highest pressure rating cap recommended by the manufacturer should be used. Such applications will still force coolant past the radiator cap when operated at sustained high RPM.
Blocking the grille openings reduces aerodynamic drag and also increases downforce. This has become “standard procedure” for qualifying. However, the engine may be damaged by overheating and subsequent heat-soaking after the engine is turned off.