take-off and landing speeds--thus shortening runway length requirements--and a thickened inboard leading edge section, with a slightly greater sweep. This modification increased the top speed over the 707-120. It had four Pratt & Whitney JT3C-7 turbojet engines producing 12500 lbf each.

At one point in the development phase, it was known as the , then , although this was the Boeing model designation of the KC-135 and remained unused for a commercial airliner until it was applied to the MD-95,