Larry, 
    I have the same problem of sorts. I have a 1937 HP-70 and it is painted dark green, but is not as dark as the older tractors, nor is it the meadow green of the newest tractors. I have 2 engine panels that are only primed and I can't match the paint....admittedly, I haven't put much effort to getting a match. I got this tractor from a fella out in eastern Iowa, I could probably search him out and see if he remembers what green he used....first thing is gonna be to get it running again... this weekend maybe.
          Cal

By the way... the 1850 block heater works well !