well since nobody wants to explain why this plane handles as poorly as it does, ie spinning ugly when it shouldnt. lets look at the speed of the plane.
38H could not make its 1,600 hp wep above 10,000ft due to innercooler limitations. it was restricted to 1,250 hp maybe 1,350 on the outside, but that is max. it still managed to do 400-405 mph on this restricted hp. now explain why the 414 mph is so widely accepted when you consider
405 mph 2,500 hp 38H
414 mph 3,200 hp 38J/L early
414 mph 3,450 hp 38L late
explain the reason why it only gained 9 mph on 700-950 hp? this is reason enough to believe the 425 mph speed for the J and 440 mph speed for the L all of these at altitudes of 25-30,000ft.
J/Ls didnt suffer from turbo problems and innercooler problems as did the H models. engine reliablity was no longer a problem as was in the H