Also, FL510GV, the C-40A (Navy) is a 737-700C (Combi...meaning a -700 with a cargo door ) The C-40B (USAF) is a BBJ I. The BBJ's have structural improvements over the 737-700/-800s. The KC-135 is the original B-717...basically a 707 with 8" narrower fuselage. (The Type Rating used to state Boeing-7071720) Later E-6/-8 and VC-137s are B-707s. EC-135s were formerly American Airlines B-707s.
Opps, Sonic, you are correct. I was thinking 717 but typed in 720. There's lots of differences including cabin, wings, etc between the 707 and the original Dash 80/717. I've never forgot that picture of Tex Johnson (?) aileron rolling the Dash 80 at (I think) the hyroplane races. Boeing had literally bet the company on that airplane and the Boeing president nearly had a seizure watching it.