It shouldn't come as a big surprise that we are not the first to contemplate this matter.
This text, "Gauge Indications on a Failed Engine",
Warbird Notes #6 was written by Mr. Randy Sohn in 1994.
I have no way of knowing whether Mr. Sohn is correct in everything he writes, but he does appear to carry a lot more credibility than most if not all of us here:
Randy Sohn .
An index to all of his "Warbird Notes" can be found here
Warbird Notes INDEX . Highly recommended!