Spit IIa is now so much more inferior to the 109

[Crumpp]

The Hurricane I Pilot's Notes mention that during take-off 2850 RPM will not be achieved with fixed-pitch propeller.

Exactly why you cannot draw blanket conclusions from engine instructions! All installations are different, even with the exact same engine/propeller combination.

The Spitfire Operating Notes distinguish between the Merlin II and Merlin III by rpm. The Merlin II is restricted to 2850 rpm and the Merlin III to 3000rpm. In a dive, both engines can momentarily achieve 3600 rpm. The run up can be deciving too as the engine is not under an airload.