re-wiring a car

Ok. I have an 84 ford mustang, and when i got it all the wires under the dash are all messed up and wired poorly. (to me it looks like whoever built/ worked on the wiring/ electrical just "nigger rigged" it. (excuse my language) ) . Anyway its just the basic wires as its just a stripped down drag car, so i was wondering how hard it would be to remove all the wiring and the fuse box and rewire everything myself?
Thanks

It would be fairly difficult. If all of the wiring and circuits were stock you could get a wiring harness complete from the boneyard and put it in. However, since the previous owner "Cobbed Up" the wiring it would be almost impossible. Many of the connectors etc. would not be there. I used to work in a shop that fixed cars that had had engine fires and had the wiring burned up. It is a time consuming task, but it can be done. We put the harness through the firewall, then connected everything in the engine bay, then connected everytning under the dash. I have always "hated" working on something that someone else had "cobbed up" so I am with you on this.