Degreeing a Cam, or not.....

Bewy said
Kent,
Post #113. The procedure I posted was for a single pattern cam. For some reason I thought you were using a SP cam. But it is a dual pattern, so it won't work. Sorry for the confusion.

Thanks for clarifying that.

Just for others looking in:

1967 383 with the small exhaust valve 516 closed chamber heads, had a dual pattern cam.

Ma Mopar designed it that way to hold the small exhaust valve open longer than the larger intake valve so it could better breath out the volume of exhaust gases that were cycling through.

So this puts the lobe centers for intake and exhaust valves at different, not equal degrees.

If my calculations are correct this would put the straight edge test on the pushrods tips on overlap at TDC (or at the recommended degrees of cam advance) leaning to the exhaust valve side, as it is staying open for a longer period of time. The lobe center degrees would not be matching, hence the angle of the straight edge.

Thanks all, find all of this very interesting. It's the whole personality of the engine when it is dialed in right.

Camshaft Lobe Separation

Definition & Description
The Lobe Separation Angle (LSA) is the distance between the centerlines of the intake and exhaust lobes on the camshaft. It is measured in degrees of camshaft rotation.

Intake Centerline + Exhaust Centerline ÷ 2

For example, if the intake is 107° and the exhaust is 117°:

107° + 117° = 224°
224° ÷ 2 = 112° (LSA)