Here is a comparison of the same intake lobe with a hot lash of .008" and .012".
.008" would be the hot lash if you ran .001" or tighter on the lash cold. The higher end of the lift curve is slightly changed, but the time off the seat at lower lifts is increased dramatically.
I have had some customers tighten up the lash to .002" to get more top end. I wonder how hot they are getting the cylinder heads and how wide the lash is really getting.
http://drcamshafts.com/pp/valve.htm