[Christ]

I can't say for sure without a flow bench and the necessary machining.

But, lets say the initial image does not cut flow, and the new configuration does.

Now, lets make it more realistic looking, and set the angle of the valve stem (using the valve's face as the axial epicenter) to about 15*. This effectively cancels the short side radius altogether, by making the flow pattern straighter. By doing so, we can effectively shrink the area of the flow tract, keeping length a constant, thus giving us an even smaller head package with nearly the same flow characteristics.

This will also set the head of the valve further out on the head's overall area, and the angle will defeat excess length making the package taller. The cams can then be spaced between the valve stems with no impact on package height, and rockers can utilize higher ratios to increase lift as necessary.

Now, we've taken a simple design, which had some problems, and by turning the valve 15* on one axis, we've effectively solved the packaging issues.

But, ok - Maybe there is a reason for the valves to be straight up, like less torsional loading on the valve stem and guide... sure, we want them straight up for a low-friction environment.

Now, we re-cut the actual flow tract so that the valve can stay perpendicular to the deckline, but the flow comes in at less of an angle to the valve stem/backside. Still removed the short side radius for the most part, opened up more area for flow across the surface of the valve, and effectively, you can still reduce tract volume, keeping length a constant, further increasing velocity, meaning that more air gets in with less work, or a net gain in VE.