WARNING: Running an underdrive main pulley on the
street is not recommended due to not being able to drive the stock alternator
enough to produce enough power for the electrical systems.
constantly over 4kRPM is a constant concern, as with race cars, you might want
to think about running an underdrive main pulley to slow all accessories
down. The stock water pump tends to cavitate the coolant when sustaining
revs over 4kRPM! By changing to an underdrive main pulley, you reduce the
chance of coolant cavitation and minimize unnecessary damage to
accessories. You can also pick up some power due to the underdrive design
by reducing the amount of engine power used to push these accessories.