On the solenoid (dunno if i spelled that right) on/near the starter, theres two small (like 16 guage) wires coming off of the solenoid. Ones purple and ones black. There is also a big black (like 8 guage) wire coming off of it. We can't figure out where the black wire goes (the small 16 guage wire). When we try to start the car, it drains all the power out of the battery (even when it has the charger on it)...We can't figure it out but we figured it had something to do with that wire. Also, we bought a hole bunch of LT1 wiring books and it didn't even show that wire on the diagram...Any thoughts on where it goes?

 

I believe that's the ground wire for the solenoid itself, since obviously the starter motor is grounded to the block.

I could be wrong.

 

That goes to the block on a little stud above the starter. It provides a ground for several swiches/relays, MAF, PCM...

 

Well first off it sounds like you have a bad battery.

Disconnect the positive terminal and use a multimeter to measure how much current in amps is being drawn between the red positive cable and the positive battery post.

If its under 0.5 amps with the car off, then your battery is bad.

If its 0.5 amps or higher, there is a light or accessory that is remaining on when the car is off.