When I pulled the engine out of the 48 2 ton, there were only a couple spots that had any paint left on it. But, those sure looked like one of the shades of Ford tractor gray that I used all the time (they used 3 shades over 40 years) on restorations.
Took a can of VHT engine paint off the shelf (ford grey) and sprayed it on the cleaned up old paint. I think it was a great match.

indoor light
http://s1276.photobucket.com/user/jsdesign2/media/100_0875_zpsa267ae8f.jpg.html

outdoor light
http://s1276.photobucket.com/user/jsdesign2/media/100_0929_zps2e586dc8.jpg.html