Camshaft Article

In another section, I explained how cams work, powerbands based on duration and how important valve lift is. There are two other areas of camshaft specs you need to know before you buy:Lobe Separation and hoe to figure out the duration you need in engines larger or smaller than 350ci. Lobe separation is the amount of degrees between the intake and exhaust lobes of a camshaft. Knowing about the separation is important because it directly affects midrange (and low end to a degree) torque, it also affects how much vacuum a motor will pull at idle (more vacuum means a better idling-less racy motor). Most stock cams from chevy motors have a separation of between 114 and 118 degrees, these cams are not optimized for power, but for economy. If you make the centerline 112 degrees, the motor will idle and make more midrange torque than a stock cam with the same durations and lift. If you want even more midrange, you can use a cam with 108 degrees separation, but it will idle poorly, and the computer will think something is wrong because the vacuum is low. Most street cars work extremely well with a cam of 112 degrees separation. One word about separation and supercharging / superchargers like cams with 115 or more degrees of separation. Why? Because you use the supercharger to force more air in than it can without, having a small separation makes the boost go in the intake valve and straight out the exhaust (because it is open longer into the intake stroke). The way to calculate the duration needed on a smaller or larger motor is easy; for every 25 cubic inches above a 350, add 5 degrees of duration to make power at the same peak as a 350. If the motor is smaller than a 350, subtract 5 degrees of duration for every 25 cubic inches the motor is smaller than a 350.

This is a list of every replacement roller cam for small block chevys (factory roller).