The primary design change between the earlier F-5E and the F-20 was the use of a single General Electric F404 engine, which was originally designed for the F/A-18 Hornet.
Põhiline tehniline muutus varasemate F-5E ja F-5G versioonidega oli F-20-el ühe General Electric F404 mootori kasutamine, mis oli algselt kavandatud F/A-18 Hornetile.