Yes, that's a fact. The clutch disengages at WOT, thus producing less drag on the engine. My Crown Vic did that too.
^What he said right there^
So did both the PI Crown Vics that I had the opportunity to drive over the years, as well as my 01 Grand Marquis, both my F150's (04 and 97), 92 Mustang LX (4 cyl), 91 Tempo, and I believe that 78 Granada I learned to drive in did too...
I haven't ever noticed that happening in my current Mustang, but then again I never get to spend a long enough time period at WOT for that to happen I guess, lest I be in excess of 100 by the time it trips