Complex sentence: Two F-84Fs were converted into experimental aircraft with an Allison XT40-A-1 turboprop engine of 5,850 shaft horsepower (4,365 kW) driving a supersonic propeller.
Split into simpler sentences: Two F-84Fs were converted into experimental aircraft. Each was fitted with a Allison XT40-A-1 turboprop engine of 5,850 shaft horsepower (4,365 kW) driving a supersonic propeller.