I just did this in my car but i didnt quite do it by the book because i have all my wiring ran throughout the inner-fenders, so i had to keep my battery relocation in the fenderwell too.
I'm sure there are a couple different ways to do it but I would run the positive wire from the battery straight to the starter. I chose to go through the interior of the car with the positive wire to avoid leaving it under the car and such. I ran it from the battery, along the back of where the back seat is there were a few factory clips that i utilized. Ran it down the drivers side - over the wheel well - under the sill plate - and there was a body plug there that i made a whole in to use as a grommet through the firewall. That ended up with the positive pretty close to the starter. Cut the wire to length,Solder and or Crimp the lug on. And attach it to the starter.
Now you can take a 'x' inch about 6gauge positive wire that you can pick up from your local parts place..that has two terminal lugs on it. One side goes to the starter (on the same stud as the battery positive), and the other side to the positive part of the stater relay.
Also, make sure you have plenty of GOOD GROUNDS. if not, you can have a lot of issues. I ran my battery ground through the trunk floor, and it attached at the frame. I have a solid drivers side motor mount which acts like a huge motor ground. I have a optima battery which has the connections at the top and the side. I bought another small battery cable for a sidepost, 12 inches long or so, 6gauge and i grounded that to the body from the battery negative sidepost connection. Then i just have a motor to body ground strap under the hood. So far, so good.
Hope that makes atleast some sense
-|Mike
