That, I don't know.
I'm sure it would have been built using parts intended for other purposes. Tractor engines are usually part of the chassis, Leylands/Nuffields, Zetors and some Fordsons are the only common exceptions where separate chassis rails supported the engine. Tractor hydraulic pumps are usually driven from within the gearbox, but its also common for it to be driven from front pulley using a short driveshaft bolted onto the mounting studs for the pulley itself. This is what I would expect in this case tbh, as a lot of the "specials" used this configuration, usually a pump intended for older JCB or similar which also drove of the front pulley in this manner. Sometimes you will find drives for hydraulic pumps taken from the timing gear for a small pump which bolts directly to the engine block, but these tend to smaller pumps used for the PAS where fitted.
