I am adding some more electical pieces and a 140 amp alternator to my car and I still have the old orriginal wire harness.What is the best way to change to change to modern wire and fuses?My car is a 65 Barracuda and I will be running a waterpump,fuel pump,duall e-fans,multi-spark ign,lights ect

DO you want to replace the entire harness or just run those items into a fuse block? If you want to rewire the entire car a painless kit is probably the best way to go, if you just want to add those items Summit/Jegs sell kits that have 4, 6, 8 and up circuts.

I used the 12 circut mini kit when I redid the my car.

http://www.ezwiring.com/wiring_harness.html

Racepac Smartwire ... Waaaay outta my budget but is pretty cool. My buddy has one on his car. Run one power wire to the box and it switches up to 30 circuits. Fully programmable and handles up to 125 amps. Single data style cable runs to switch panels. Output wires from the box to each accessory. Program parameters from the laptop. http://www.racepaksmartwire.com/Smartwire_Home.aspx

Yes you'd run basically 2 systems. One thru the volage regulator and the other w/o. Why do you feel the need for such a big draw alternator? That will crate a bigger draw on the engine. I've used several 65-70amp alts and ran H20 and electric fuel pumps w/o an issue. So guys even run a field kill switch at the track, this is supposed to be good for a few HP so I hear. Many of the race cars I see, if they run and alt run as small a unit as possible. Some of the "street" guys run lawn tractor alternators. Your fans and pumps shouldn't be pulling that many amps. I thought those high output batteries were for new cars w/ bunches of computers and guys w/ big booming sterios.

I did this not to long ago with my 68 Barracuda. I knew I needed to undo my hack wiring for my pump and fans etc. I also knew I needed a better alternator to support these systems. I was also very aware I didn't want to rewire the entire cars lights etc.

I went and removed every bit of wiring that I added on. I then cut the engine part out of the under hood harness. Take note, on my 68 the horn wire was in that bulkhead connection despite the fact that it is really should be in the lighting section as that's where it runs. This caused me lots of problems when I tried to fix the horn for drag week LOL.

I relocated my battery to the trunk. I made a 12 circuit relay panel that is located in the glove box. Don't make a relay panel, it will cost less to buy one don't ask me how i know. I ran a 4 gauge wire to a power stud mounted above the kick panel on the passenger side, from this I powered my relay panel. I then took the ammeter wire and moved it to this power stud. This eliminated the bulkhead connection and powered up the factory fuse block and allowed the lights etc to all work. This was a HUGE improvement, everything works so much better and brighter with no ammeter and no bulkhead connection.

For an alternator I ended up with a GM CS130, not really by choice but because it fits the alternator bracket that goes with my mezziere pump. It also happens to be a readily available piece that is 110amps or so.

I wired the alternator up off of a diagram I found online with a charge light and ran the power wire to my power distribution point near the relay panel. I have 14+ volts at a 1000 rpm idle with everything on, lights, pumps, fans, etc.

I also put a jeep starter relay at the back of the car and ran the starter wire from the back up to the starter. The jeep solenoid works off of a ground just like the factory starter relay, this lets the neutral safety switch work like factory. This also allows that big long starter cable to only be hot when the starter button is pushed. This also cleans up the engine compartment a lot.

Now, the only problem with this setup is this. I ran the field wire from the alternator all the way back to the cutoff switch on the car. The cutoff switch has two sets of poles one for the alternator and one for the power wires. Somewhere I have wired it wrong and it doesn't shut the car off. I believe I need to bring the hot wire from the alternator to the battery side of the cutoff switch.

Summary, lights all work just like factory, wipers as well. Everything else that makes the car run is powered from my relay panel that is switched off of my center console. I also have a few circuits left in case I add something else to the car like nitrous or another fan etc.

Like mentioned above. I too added a separate high amp circuit to feed all my high current draw items.

I used the Mad Electric concept of a main distribution lug under the hood to feed all the high amp draw stuff. The main distribution lug fed by a reworked A/C Delco CS 144 alternator. It puts out over 115 amps at low idle.

All large gauge cables are protected by high amp marine fuses, all circuits protedcted by a marine grade fuse block and used relays on all add-ons.

I put the battery in the trunk, kept all high amp draw loads out of the passenger compartment including headlights which are now on relays. The interior stuff that passes through the bulkhead connector is now essencially just another low amp circuit that's fed off the main distribution lug.

The car wiring can be put back to stock in about a couple of hours by removing the new "secondary" high amp distribution circuit.