[ACE-OF-ACES]

It's a nice idea, but your test itself doesn't really show much considering the many differences between the P-51B and the F-51D. The P-51B *was* faster than any of the D models at the same manifold pressure, as far as I'm aware.
I know it's not your fault that you were forced to use this data, but it still makes your comparison pretty irrelevant.

Actully I took into account the differences

Thus not irrelevant

Now if you have any questions as to how I took the differences into consideration, click on the link and read about it. After reading it, if you have any questions about it feel free to ask them here or via PM. And if you think you have a better way to account for said differences, I am more than happy to hear them and if you can show that your method produces better results I will be more than happy to use your method.