What numbers do yo have to back up the claim of post-war Allisons being more powerful than the post-war Merlins at high altitude, as well as in 1945? What are the versions in question?For most of the war, the Merlin WAS a better high-altitude engine. In 1945, not really. Post-war, the Allisons that were developed were more powerful than post-war Merlins at high altitude, where you seem to want to be.
The Allison was much easier to overhaul, consuming anywhere from a high of about 67% of the man-hours required for a Merlin down to only 55% late war, and the TBO was longer. I have an old post which said that TBOs were set based on engine performance. That is incorrect. TBOs were set so that a certain percentage (usually 98.5% or more) of the engine cases sent back for overhaul were, in fact, able to overhauled instead of being scrapped. Early-on, both Merlins and Allisons were TBO at about 200 - 250 hours. Later, Merlins went up to around 350 hours and Allison went up to about 500 hours. The change didn't so much reflect reliability as much as the engine cases/parts being able to be overhauled.
Let's say your numbers here are correct.
How much of a good thing is the perfectly reliable V-1710-39 above France, UK or Belgium in better part of 1942, when compared with a less perfectly reliable Merlin 45?
Or, in 1943, above West Europe or Italy, the perfectly reliable V-1710-81 vs. the less perfectly reliable Merlin 60 series?
You are knocking on the wrong doors there.Everything I've found indicates that the Allison, when it initially was deployed to Europe had 2 main issues (fuel, intake and, perhaps less well known, incorrect operation techniques), making it less reliable than the Merlin (Allison time bomb period). When those issues were solved (about late summer 1943), the Allison was as or more reliable, based on parts wear out, and held a tune longer than the Merlin.
Main issue of the V-1710 when initially deployed in ETO was that it lagged behind in power at higher altitudes when compared with Merlin. More seriously, it was also badly out-performed by German engines.
Lack of performance at higher altitudes was due to the low capacity of it's S/C. There was no quick fix for that, Allison was the institution to do it across the pond.