STS ?? .. I see it AT threads discussing TC's ... (I like accronyms!! .. I can't spell worth a crap! .. and I type even worse))

Definition: Lobe center is the amount of camshaft degrees between the point of maximum lift on the intake lobe and the point of maximum lift on the exhaust side of a given pair of cam lobes. As an example, lobe center is calculated for cylinder number one only and does not deviate between number one and the other cylinders in the powerplant. To make a representative sketch of lobe center, draw a line between the very center of a camshaft intake lobe and then draw a similar line through the respective exhaust lobe for the same cylinder. The number of camshaft degrees between these two imaginary lines is the camshaft lobe center.

Also called lobe displacement angle (LDA), the lobe center has a definite bearing on how a particular camshaft will operate in a specific powerplant. If the lobe center of the camshaft is increased, the valve overlap will be decreased. The overlap decrease is created because the exhaust timing will occur earlier and the intake timing event will occur later in relation to crankshaft position. Conversely, if the lobe center or displacement angle is decreased, overlap increases. Note that lobe center cannot be changed once a camshaft has been ground.