The Can of worms maybe not everyone (including me) completely understands,,,,,

General theory states that timing your Intake centerline to allowing the valve to approach maximum lift at or near the the point of maximum piston velocity (where the connecting rod is just passing the 90 degree right angle to the crank throw) is very beneficial for torque output. Note: NOT the same as 90 degrees past TDC but later. This point where the Right angle is achieved is a constant but will vary depending on rod length (for any given stroke), but it is calculable through Trig.

But if you can maintain a strong unrestricted optimum air/fuel ratio charge flowing past your intake valve at high piston speeds ,The fact that your intake is closing earlier (relative to a later Intake centerline) might actually cost you some power in terms of cylinder filling as the piston is coming back up the bore.

When you get it right, the ramming effect of a strong intake tract will overcome the loss of displacement as the piston is coming back up the bore past BDC which effectively increases dynamic compression. the issue (if you can visualize it) is that as the piston is bottoming and heading back up the bore, the intake valve is rapidly closing the flow window for the port to keep filling the hole.

Where the charge keeps filling as the piston volume is reducing/passing BDC and fully closing is in effect 'supercharging' the lower effective displacement.....that's the key fascination for me....and for any motor and head combination (within the limitations of whet your working with) is what I'm always seeking to achieve is the best balance of both. If you don't have enough intake charge, the piston will push (reversion) the mixture back toward the intake, but if the charge is high enough, you trap more mixture than the cylinder (at that instant where both valves are closed) can hold statically...before actual mechanical compression begins.

I've been doing a lot of research on what Bob Glidden was doing in the 70's with the Cleveland fords and the W2 mopar wedges. It fascinates me how the intake charge, the cam centerline and the intake closing all work together. And also how the torque and power peaks interact and where valve overlap can be (and is) both beneficial and detrimental....depending on what part of the power curve you are looking at.

It was also how I figured out how the F.A.S.T. cars could be getting the amazing outputs they were achieving.

I'm sorry for rambling but I'm sure a lot of you will know what i'm getting at.

I'm just seeking additional insight and understanding from guys with a lot more depth of knowledge than I have.