Abstract: The present application discloses an engine, a fuel system for an engine, and a method of installing the fuel system and converting an engine to operate using a second fuel. In one exemplary embodiment, the fuel system comprises at least one fuel rail for the second fuel, at least one connector attached to the fuel rail and configured to fluidly connect the fuel rail to a second fuel injector, and at least one fuel injector adapter configured to receive a discharge end of the second fuel injector and position the discharge end in fluid communication with at least one of an intake port and a combustion chamber of the engine. The fuel system is configured such that the engine operates using the second fuel without removal or use of the original fuel rails and original fuel injectors.