PHP Dada

Hello all I have a 1991 ford mustang that was a 4 banger 2.3L now it has a 5.0L 750 carb I need to know a few things:

1: Do I need to change the wire harness under the dash to V8 as well
2: I have the 4 banger clusters and I want to put the 140mph but I dont know which year do I get clusters wise.
3: can I use a EFI motor with out vac hoses just motor and wire harness


Thanks alot for all that help you give me I will post pics of my 1991 soon by tonight

racer44

should just get v8 complete harness would make it alot easier