The final production version of the Kingcobra was the RP-63G, which was a dedicated flying target version of the Kingcobra. The manufacture of the RP-63G actually continued on into 1946.
Two P-63Cs (43-11723 and 11724) were taken off the production line and modified to RP-63G configuration. Lights were inset into the fuselage sides and into the top surfaces of the outer wings to indicate when the plane was hit, and a flush dorsal air intake was fitted. 450 RP-63Gs were ordered into production as dedicated flying targets (the earlier "Pinballs" being conversions on the production line of P-63 fighters). The RP-63G was powered by the Allison V-1710-135 engine.
However, only 30 production RP-63Gs were built (serials were 45-57283/57312) before production of the Kingcobra finally came to an end. The order for 420 more RP-63Gs were cancelled before they could be built.
A single RP-63G (serial number 45-57300) was fitted with an experimental V-tailed assembly a la Beechcraft Bonanza.
In 1948, the RP-63G was redesignated QF-63G, Q being a pilotless drone classification. However, it was never actually flown as a pilotless drone.
An RP-63G (45-57295) has been on outdoor display at Lackland AFB in Texas.