SB/BB Moroso crank pulley

Mopardude,

Underdrive pulleys increase power by reducing the workload of the motor, (think like a smaller sprocket on the front of a bike) smaller diameter=easier to spin... they are great for race car, be careful on a street car because the smaller diameter pulley means the accessories spin slower.

OHHH....Okay, I got it! Thank you for the explanation! Good luck with the sale!