WHAT wiring?? Hehe try working on an injected motor sometime, those old carbies are simple as hey :)
You might need to lengthen wires such as alternator, temp. gauge, etc. depending on the position on the new motor. Other than that, I doubt very much that you will have to add more than one or two wires overall.
The gearbox and the engine/radiator mounts will be your biggest headache IMO. Tailshafts may be too long or short, requiring either searching out one that will fit or more likely, having a v8 shaft cut down to fit.
Also I dunno how long the old diff will last
Proud TQE Operator and President of SEFAG - the Society for the Elimination of Ford Automatic Gearboxes
Pacemaker headers + 2.5" exhaust
EF Fairmont interior
Lowered King springs
5 speed manual
Newest mod: EF Ghia wiring loom and dash