Third Generation F-Body Message Boards

So Im learning as I go on this build, now the time has come to get the drivetrain in but first I need to clean up this wiring mess I have under the dash. The old setup in the car was a 305 carbed with mech feul pump. I will be rebuilding the 700r4 and puting in an old school 350 carbed with mech fuel pump. I was told by painless that I wont need a new harness he just told me to take out the computer and follow the ecm wires back to the fuse block and pull them out. Get an MSD ingnition and I should be good to go. I guess where im stumped is indentifying all the wires I dont need and the ones I do on the harness going into the engine bay and also the wires under the dash. I would like to get power to the gauges and rear lights to make sure stuff is working also So I need someone that knows alittle about cars to help me get started. I am not the best mechanic by no means but with the right instruction I know I can do this job. I dont want to hack the car all up trying to figure out what is what. Anyone want to take me under thier wing and help me out ?

This is where I am at with this build: i will take some picks of the mess under the dash and post soon... thanks Attachment 354485