G'day Brisso57
As was stated by both JDNSW and Phoenix the series2/2a 4 cylinder motor in Aust Military use was basicaly the civilian version with the added extras of the 8 bladed fan, double pulley on crank and water pump, also generator (you can use a double pulley alternator) they also had an extended radiator shield, and heatsheild on the exhaust, a gearbox/engine steady bar from the bellhousing to chassis x member at gearbox, some special purpose vehicles,had an Oil Cooler-Firetrucks, and FFR's had a special mounting for the 24volt Radio Alternator fitted on extended Head bolts on some early Ser 2a's and I have seen one ex 131 Div Loc vehicle with the special front timing case cover which had the 24v generator mounting in it, the front mounted exhaust was fitted to Workshop trucks and some FFR's all had the coil bracket mounting on the right side of the cylinder block on a bracket held by the head bolts just after the distributor, this was done so that an engine could be removed/installed as a complete unit (connect-fuel,starter, rad hoses)and away you go.
cheers