- Mopar Performance parts make engines powerful.New car petrol engines image by Christopher Dodge from Fotolia.com
A registered trademark of the Chrysler Group, Mopar defines power in automobile engines with Mopar Performance products found in muscle, street, speed and trail vehicles. The Mopar Performance cam refers to a part that attaches to the camshaft and causes the engine valves to open and close. The cam with its detailed specifications contributes to Mopar power performance.
- Duration details how long the valve remains open. As the camshaft rotates, the cams along its structure cause the valves to open and shut. The manner of measuring duration relates to crankshaft rotation. The number given describes how far the crankshaft rotates while the valve remains open. That number expresses itself in degrees of rotation. For a Mopar Performance 426 Hemi Purple Shaft Camshaft the duration measures 241 degrees.
Rocker Arm Ratio
- This term defines the difference between the pushrod and valve stem side of the rocker axis point, expressed as a ratio. The rocker ratio exists due to the fact that the pushrod side of the rocker is closer to the rocker's pivot than the valve side. For Mopar performance cams it is listed as 1.5:1. The significance of the ratio lies in the fact that the ratio is used as a multiplier in determining the gross lift, or how far the valve opens.
- Lift, the distance the valves open, measures in fractions of an inch. For the 426, lift measures .484 inch at intake and .475 inch at exhaust.