"Race" engines have camshafts with more agressive lobe lift profiles on the cams PLUS much higher valve spring pressures (so they can turn much higher rpm levels, for extended periods, with these higher lift longer duration flat tappet camshafts they have to have to be competitive in their respective classes) to do what they do. Higher spring pressures, particularly, are a contributor to the pressure the cam lobe sees from the flat tappet valve lifter. Similar higher contact pressures also exist at the rocker arm pivots and interfaces with the pushrods and valve stems. Greater side loadings also exist on the valve guides from the sliding motion (of the rocker arm tip across the top of the valve stem as it forces the valve open and, to a lesser extent, as the valve closes) of the valve as it opens and closes. Plus, if any "harm" is to be done to the motor with the elevated ZDDP levels, the oil does NOT stay in the engine much past the particular race event . . . i.e., NOT 3000+ miles.
"Race" engines are a specific application per se, with might have a bearing on "street" or "hot rod" motors, but more remotely for "street" or "stock" motors which most of us have.
One article I saw mentioned that detergency additives can wipe out zddp levels, so the two need to be balanced. Seems like I saw that in a VW forum or on the LNEngineering website?
As always, oil base stocks, anti-wear additives, detergency additives, and other items in the total oil formulation are what usually is important rather than just looking at ONE aspect of the total combination . . . I suspect. Some generalizations might be made, but only ones which might work for one brand of oil and/or one viscosity rating of a particular brand of oil.
Just some thoughts,
CBODY67