XF-104 with a Buick J65-B-3 turbojet engine in 1953, of interest is the to the rear hinged Electronic bay

The production aircraft was planned for a General Electric J79 turbojet but that engine would not be ready soon enough, so both prototypes were designed to use a Buick-built J65-B-3, 
a licensed version of the British Armstrong Siddeley Sapphire turbojet engine. XF-104 53-7787 had been built with an afterburning Wright J65-W-7 turbojet, rated at 7,800 pounds of thrust, 
and 10,200 pounds of thrust with afterburner. The J65 was a single-shaft axial-flow turbojet with a 13-stage compressor, annular combustion chamber, and 2-stage turbine.

While the first prototype, 53-7776, was equipped with a Buick J65-B-3 turbojet engine, the second used a Wright Aeronautical Division J65-W-6 with afterburner. 
Both were improved derivatives of the Armstrong Siddely Sa.6 Sapphire, built under license. 
The J65-B-3 was rated at 7,330 pounds of thrust, and the J65-W-6, rated at 7,800 pounds (34.70 kilonewtons), and 10,500 pounds (46.71 kilonewtons) with afterburner.

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