No, way too difficult, lots of problems, don't do it. You should sell the engine or better still I'll get rid of it for you ;)
I'll tell you what I'm aware of, the car is a bit of a mechano kit so as long as you have all the bits it can be done.
The pedal box bolts into the cab, so you can change that easily enough.
The rad is bigger, you need a good one for the 4.2 and the auto uses if for oil cooling as well as the hairy sausage behind the grille, the RH end of the rad cools the engine oil.
The wiring loom for the engine connects to the main loom in the driver's footwell with 2 plugs, one white one blue, if you have all the brackets for the ECU and you can find the plugs in your car then it plugs in.
You'll need the petrol tank and pipes, not only is there a pump in the EFi tank but petrol requires a flourinated tank that might not be fitted to the TDi.
Things like the glow plug wiring might just unplug, but you need to check.
The auto box sits further back on the V8, you'll need different propshafts and gearbox crossmember. The 3.9 and 4.2 exhausts are routed below the crossmember which is tubular, the 3.5 had a square one with the exhaust above it but the exhaust is smaller.
The 200 series airbox is different, not a mojor problem, the header tank is the same.
The engine mounts I 'm not sure of on the 200 but are different on the 300 to a V8, that might be one of your big problems as it will involved welding to the chassis, not sure how you stand with the DVLA these days :roll:
There's bound to be other things that someone else will hopefully think of :-k
