Does installing a lighter crank pulley increase horsepower?

Yes, installing a lighter crank pulley can increase horsepower by reducing the rotational mass that the engine has to turn, allowing it to rev more freely and efficiently. This can lead to improved engine response and acceleration. However, the actual horsepower gains depend on various factors, including the engine's design, tuning, and other modifications. It's important to note that while a lighter crank pulley can enhance performance, it may also affect accessory drive systems and overall engine balance.