Thank you Moody Blue. At last a reference, as opposed to someone telling us what he thinks will happen.
"Cut a mixture and just leave the throttle alone where it was set at cruise, lets say, for example in this case, 27". If you can visualize a big air pump, that is exactly what the engine is, with the throttle located at the intake. After seeing for yourself that the MP stays unmoving at 27" ....."
"The engine keeps turning and as long as it does the oil pump keeps pumping, right? So the oil pressure stays up and doesn't give you a clue about which one failed. Over the short period we're discussing here the temperature stays up too."
"When we cut the mixture at cruise airspeed the RPM sagged about a hundred and then went right back to where it had been. Let's analyze that for a minute. The engine is still turning so the oil pump is still putting out normal pressure. Where does the prop governor get its supply? That's right, from engine oil pressure. So it keeps doing its thing according to your request through the prop control. You had the control set to cruise RPM so (after a second or two of decrease followed by an immediate increase as the blades assume a new angle) that's what it delivers. It will as long as it has oil pressure and, with this proviso, that the cruise speed stays high enough so that the blades don't reach the pitch stops while trying to maintain the requested RPM."
This all exactly what virgo wanted confirmed, and exactly what a few of us who have actually flown supercharged (NOT turbocharged) multi's have been saying