Conslaw
Senior Airman
Planes and Pilots of WWII (web Page) has some other charts on speed and climb of P-38L models Climb clean WEP 4.9min to 20,000ft this is also stated in the web page p38(CCJordon). They also show the top speed of the P-38L again clean half load of fuel and full ammo/gun ballast of 443 @ WEP (the 414 often shown is METO power as are all other P-38 specs.) and no I never ment the P-38 was in the leauge of the P-51H or P-47N in the 470 region.
I never mentioned the K model as it was never produced though it's top speed was est to be over 450mph.
P-38L's WEP top air speed of 443 MPH, was what- 25,000, 26,000 feet? What is the P-38's compressibility speed at that altitude? It seems to me that they may have been at a "coffin corner".