In this episode of Engine Masters, presented by AMSOIL, Freiburger, Dulcich, and Westech's Steve Brul school YouTube on what camshaft variables you need to know and what they mean when making horsepower in your next project. Camshaft specs are one of the most black magic aspects of engine building -- being able to decipher the main ingredientscan mean a big difference in horsepower and torque, and where those numbers peak.

Lift

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Lift is measured at the valve and it dictates far the valve lifts off of the seat. This means that the valve can pass more air while its open during the intake or exhaust stroke, and more lift means generally means more horsepower (if the cylinder head can support the needed airflow). Mild street engines will typically see around .500" (half-inch) lift, while a high-performance cam will be up in the range of .750" (three-quarter of an inch) lift.

Duration

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Duration dictates how long the valve is open during the intake or exhaust strokes, which is set by the width of the camshaft's lobe profile. Measured in degrees of camshaft rotation, and like the lift spec, more duration means more horsepower.

Lobe Separation Angle

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LSA is what's responsible for a smooth stock idle or a choppy race cam lope. LSA refers to the time where both the intake and exhaust valves are open together, measured in degrees of crankshaft rotation. More than anything, LSA dictates where an engine will makes its peak horsepower and torque numbers. More overlap (where the intake and exhaust valves stay open longer) with a tight LSA will move the engine's peak power higher (so long as the cylinder head has the volume to supporthigh-RPM flow) while promoting more thorough cylinder scavenging, while a wide LSA with less overlap will favor low RPM applications.