Just came across this memorandum, Bill. Thought I'd post it out of interest only.
I have no background on it, but it seems like 7 1/2 hours at 75" WER goes a long way toward backing up the fact that Allisons were flown at 75" MAP, as reported by more than a few people. Retired General John Allison (no relation) said the P-40 "woke up" when you flew it at 75" and turned into a really good fighter. But, that is hearsay and I can't claim any first-hand knowledge about it other than hearsay from a guy who was there.
We've run an Allison at 57" on a run stand, but we didn't have an 130 - 145 PN fuel to go higher and didn't have any reason to do so in any case. Joe Yancey has tractor-pull customers in Europe who run his Allisons at 4,500 rpm with no ill effects! Of course, they are running at those speeds for a relatively short time ... a fraction of a minute. Don't get me wrong, the Merlin tractor guys ALSO run at high rpm and power. But, I don't have any Merlin guys talking with me about their settings and experiences, so I can't say much about the Merlin tractor-pull Merlin engines other than they run well, as expected, and the really GOOD ones use Allison G-series rods.