Yes. The chart goes up to 2550 and and this line drawn above the 2500 line in the chart is quite close, meaning that the engine was close to peak rpm's and would not be producing much more power at 2600.
Then about what the +250 mm and 2550 RPM would add: I already explained that with the Spitfire MkI chart I linked to in post #334: The extra 50 rpm's from 2500 move the FTH speed a little towards higher speeds, but this is only marginal adding just a few mph at the FTH. The main gain is at lower latitudes, not at the FTH. Just as the effects on the Spitfire MkI when going from 6.25 to 12 and ultimately +16 boost.
I can't agree that the Spitfire's behavior is relevant to the behavior of A6M2. The A6M2 has substantially MORE power at its critical altitude than it does at sea level.
Its rated power is higher than its takeoff power. When you add in a bit more RPM and Manifold Pressure as Overboost at altitude, the result isn't going to be lower than it was at low altitude.
And I don't understand why you are so fixated with "bent birds"? Unless a rebuilt aircraft is put together in a very bad way the effects on performance would be minimal. But since you seem to think there are many mph to be had here, just what was "bent" and how many mph would "un-bending" these defects do? 1,2, 3 or 5 or 10 mph? Because if this was missed by the BuAer engineers in charge of the testing, they were not very good at their jobs were they?
The defects were noted in the "Sanders Rpt" which has been posted. Please look at the "Notes" section on "Page 3" of the report.
It also states that that they believed they compensated for this by running higher than rated power but the reality was that they were not.
35 inches MP is only +129 mm which is well below rated power.
Note also on this page the comments that they were having some problems with getting the carburetor to work correctly. In reality, they never really got things to work completely right.
Note on the first page of this report (unnumbered), that there is a statement that there is a comment on the propeller pitch and the "damaged condition" of the aircraft.
The people at San Diego did their jobs as best they could but without spare parts, they had to make do with what they had. There certainly were remaining defects which affected performance.
We have been so fixated with speeds so far in this thread, that we have forgotten to consider that the climb rates in the US tests tell a story as well: And if you look at the climb rates in those tests you can see that the engines were delivering according to specs since they measured a bit over 2700 fpm SL climb rate for the A6M2's in both those tests, which is just as expected looking at the power loading W/P. So this proves without a shadow of a doubt that there was nothing wrong with the engines and that that reason for the low revs they measured when testing initially was due to the propeller pitch setting being adjusted for range, and not performance.
As stated before, I don't think it is reasonable to configure a carrier borne fighter in such a manner and I do not believe this was actually done.
If you REALLY want to work with Power to Weight ratios, take a look at the A6M3 from Eagle Farm.
The actual output of the engine is listed in the report and it compares quite interestingly to the A6M2, especially the Akutan A6M2.
The SL output is 960 HP which is about 20 HP higher than the rating for the typical A6M2, but the aircraft also weighs about 100 pounds more than the weight of the Akutan A6M2 as tested. Is that a pretty even match? I think so.
Note that their climb rate is over 3400 FPM rather than 2700 FPM. What does that say about your argument about power to weight being as expected???
Note also that coarsening the pitch of a propeller to bring the revs down should not affect the maximum speed. In fact, the commentary is that messing with the propeller to reduce pitch most likely cost them speed (first page of the Sanders Rpt).