4cyl to 5.0 questions

i was wondering if any of you guys that have done this 2.3 to 5.0 swap have used just the wiring harness for the motor or if you had to use both halves?
i have also heard that the 5.0 gauge cluster will not work with the 4cyl harness.
this is my first fox project so any advice, tips, or tricks would be much appreciated!
 
the tac will be off for some reason my fuel gage and oil press dont work eather you will need the fuel line from a 5.0 and all the front wiring for the car excpet for under the dash if you have an 89 you need the wireing from the 89 or if you have a 90-93 the wiring for one of those years
 
I did the swap on my 91LX. I used a engine harness out of a V-8 91 and a A9P computer. My stock 4 banger gauges worked fine, with the tack reading double. I later on swaped it out for a V-8 cluster and all the gauges along with the tack read perfect.