Nice work: the metal effect is very well done, and that's very hard to do. I'm not sure what you mean by converting a P-51B to a P-51C? They are rather identical, are they not?
I'd point out two minor details: you've added some highlight around the intake just below and behind the spinner. It looks as if the intake bulged away from the fuselage, which is the case but overdone and too sharp on your profile IMO:
Also, I think the ventral intake's shape is wrong. The part between the fuselage proper and the top section of the intake is "blended in" which was not the case on the actual aircraft:
I'm aware the pictures are nowhere near perfect but that's all I have at my disposition for the moment. I can find some more explicit ones if you need them.
