I have a 67 SS. The motor is out. I want to power up the electrical system to check the lights and such. Wich wires do i hook to the pos. batt. lead? since there is no alt. in the car do i leave those three disconnected. I noticed a heavier gauge wire(not as thick as the starter) lead near the batt. tray but goes to some little square box near the pass. headlight.(not the volt. reg., thats on the other side of the rad. mount).Any ideas?

I have a 67 SS. The motor is out. I want to power up the electrical system to check the lights and such. Wich wires do i hook to the pos. batt. lead? since there is no alt. in the car do i leave those three disconnected. I noticed a heavier gauge wire(not as thick as the starter) lead near the batt. tray but goes to some little square box near the pass. headlight.(not the volt. reg., thats on the other side of the rad. mount).Any ideas?

That heavier wire is the main feed for the -entire- car. As long as you connect a +12 volts source (I would recommend the car batter with a fuse (30 amp would be good for testing purposes) in line with the (+) terminal and the other end of the power feed to the junction block (that's the little box with a stud sticking out of it). Connect the battery (-) to a good clean metal area.

Important Wrap electrical tape over any bare connectors that would normally have power on them once you power up. Some examples would be the starter's main battery supply wire, and the red wire that mounts to the stud on the back of the alternator. Any bare/cut/damaged wires should also be separated and taped up as well. Failure to do so will results in nasty/dangerous sparks.