Instrument cluster and all dash components are different in a HJ75, although the glow & fuel relays may look the same but they are different numbers. Also the glow system on the hj47 will be a super glow system whereas the hj75 I think you will find is a delayed glow system.
It is possible but a lot of work. I just put a 12Ht diesel into a 40 series and converted the edic relay to turn off vsv on the inlet manifold, changed the wiring loom to accept the larger pinned fuel relay from the 60 series and changed the glow relays to adapted to the heat screen of the 12ht.
You really need to know your electrical's to do these sorts of changes.