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I realize this may fly in the face of everything you have been told or have read before, but it’s not that hard to see it must be so.
Let’s do one of those mental experiments to establish overlap as a highly influential criteria.
The area it has to accomplish this in a typical V-8 is about equal to a 15/16-inch-diameter hole.
This means the piston moving rapidly down the bore in the middle of its induction stroke can draw through the intake manifold and right on through the overlapping valves to that cylinder’s exhaust.Assuming a totally rigid valvetrain, the engine sees the last of these three.Because the valve lash operates through a step-up rocker ratio, the lash between a solid lifter and the cam is usually smaller than the 0.020 inches used for the advertised duration, so the duration at the lash point is often longer by some 6-12 degrees.It’s not hard to see that, even in the case of a cam of only about 280 degrees with 64 degrees of overlap, the overlap acts like an unwanted hole nearly an inch in diameter in the intake manifold.OK, so overlap, or at least too much of it, is not good for a street-driven engine.
The answer here is that it depends on the valve sizes in relation to the cylinder displacement.