Test results are presented to evaluate a range of nozzle types and installations for a twin-engine supersonic fighter. At subsonic, transonic, and supersonic Mach numbers, 0.6—1.3 and 2.2, simulated forebodies were mated to five aft-fuselage shapes installed with five interchangeable variable-throat nozzle types: Iris, C-D Iris, Variable Flap Ejector, Plug, and Blow-In-Door Ejector. A dual force balance system, recording static thrust, aft-fuselage drag, and over-all afterbody thrust minus drag, was used to assess the effects of engine spacing, peripheral blockage, nozzle/fuselage combination, jet area, nozzle pressure ratio, and tunnel Mach number on interference drag. The results reveal that marked reductions in high subsonic interference drag are possible with widely spaced designs and Iris type nozzles.