The F-84G incorporated a number of changes on the earlier F-84E. Incorporating in flight refueling equipment with wing receptacle in port wing for use with the Boeing developed and SAC endorsed "flying boom" system, the F-84G was the first fighter built with the capability of refueling in flight and at a single point. An Allison J35 A-29 engine, autopilot, A4 gunsight, a new instrument landing system, and a revised armament, with up to 4,000 lb. of external stores were also included. The F-84G was also the first single seat fighter bomber with atomic capability.