318 to 360

I thought I did well, rats!!!

OK, the standard head has a rocker ratio of 1.5. It magnifies the actual cam lift from off the lobe. When you change to a Magnum head, there rocker ratio is 1.6. This means the lift at the valve will be greater due to the rocker ams great ratio.

What your doing to find out what the new actual valve lift is, simple math.

The current lift is, for say, .500 with the standard rocker arm. Divide the rocker arms ratio into the cam lift. That is 1.5 into .500 which equals endless amount of 3's. (.333333333333333333333)

We'll just use .333 which is the actual cam lobe lift and multiply it by the new rocker ratio from the Magnum head which is 1.6.

1.6 X's .333 = .533

The change to the Magnums rocker arm