Matt-113

Hey up.. I'm new to this form and to this, I have just got hold of an early 90's disco v8 the v8 runs sweet as a nut but its to thirsty so I wondered about putting a 200tdi engine and ecu but leaving the v8 gear box in I just wondered if any knew how hard it is and what would I need to do, I know about the fuel tank and a return pipe, glow plugs, bell housing, radiator and the engine mounts. Didn't know of their was anything else I was missing lol? Any advise on this would be greatly appreciated