What does that mean.

Seems to me that it would be where the walls of the combustion chamber would overlap the valve face but if thats the case than cant imagine how one would get the valve in and out of the head?

Here's an article with photos: Valve Shrouding

Basically, it means that the edge of the valve opening is close enough to the edge of the combustion chamber or cylinder wall that the flow is restricted.

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"When you find a big kettle of crazy, it's best not to stir it." - Pointy-haired Boss

1964 Valiant V200, 225/Pushbutton 904
BBD, CAI, HEI, LBP, AC, AM/FM/USB, EIEIO

Very nice, that article answered a few other questions that I had as well. Thanks for providing the link!