Check the length
Don't know about this particular swap but will give a few suggestions: (1)check length of frame to see what will go in the hole without frame lengthening, (2) see if the 619 has an industrial SAE type flywheel housing (makes adopting to the tranny a lot easier), (3) how is the hydraulic pump mounted? (4) Is there enough room for an air to air cooler in front of radiator? These are some of my first inspections. Engine choices would be the 8.3 or L10 cummins (do not get a low flow engine: small radiator hoses), a DT 466 binder would work as would the 4 cylinder 50 series detroit (short for easy room fitting) the old 6V detroits would be a possible choice but noisy and use a little more fuel. You could go with a deutz engine and do away with the radiator for room. An old 237 mack truck engine may be small enough to go in the engine compartment should be cheap and they have great torque. Good luck on your project.