The following report covers the design, and testing of a dedicated hydrogen-fueled engine. Subsequent modifications to the design are also covered. Both part-load and full-load data were taken under laboratory conditions. The engine design included a billet aluminum single combustion chamber cylinder-head with one intake valve, two sodium cooled exhaust valves, and two spark plugs. The cylinder-head design also included drilled cooling passages. The fuel-delivery system initially employed two modified Siemens electrically actuated fuel injectors. Subsequent modifications allowed operation with a premixed hydrogen-air mixture. The exhaust system included two separate headers, one for each exhaust port. The piston/ring combination was designed specifically for hydrogen operation.