OK this is whats racking my brain this winter. I have a 70 Chevelle SS 396/4002 350hp, 4spd (m20), Tach and gauges from the factory. Its a real SS with #s and build sheet. I have a big problem, when I shut the car off it drains the battery in about a half hour. It charges and runs but I have to disconnect the battery when I turn it off or I wont get home. I also tried to look for any broblems like broken wires or ground that do and dont belong.
I tried a new alt, new voltage regulater, I tried disconnecting an after market radio and everything else I could think of, I tried a new head light switch and I tried useing a meter and pulling the fuses and to if it drops. NONE worked.
Any ideas? Should I pull the outer side of the fuse box and rebuild the harness? I just cant figur it out.
Thanks, Jason

Do you think that your problem would be different if you didn't have a real SS with #s and build sheet, or do you think these are part of the problem?

There a few threads here with good info for solving your problem, like this one:

http://www.chevelles.com/forums/showthread.php?t=208686

No I just wanted to let people know what I have to eliminate some of the questions. I just wanted people to know I wasnt trying to clone the car and it lead to a charging problem. The options on the car are factory original except a radio, power steering and under dash gauges.

Well, it still sounds like the alternator to me....have it checked at a reputable auto parts store, i.e. performance shop or mom and pop shop, NOT the local Auto Zone, Schucks, etc. Also, what quality alternator did you buy, rebuilt or new? Name brand or Chinese?

It takes a pretty large current draw to drain a battery in a 1/2 hr. Are you sure the battery is fully charged? (fully charged battery is about 12.6 volts)The battery may also be bad. (have it load tested)

To test for the drain, disconnect any clocks and radio with memory, with the car off and everything turned off, (be sure doors are closed) disconnect pos battery cable and connect a test light inline between the cable and the battery, (do not let cable touch ground) with a drain the light will be lit. You need to make the light go out to find the drain. Disconnect things one at a time till the light goes out. First disconnect the alternator and voltage regulator plug, then fuses at the fuse box.

make sure the glove box light (if equipped) go out when closed.

As Greg said 1/2 hr is pretty fast to drain a fully charged good battery. That thing should be boiling hot and melting wires unless it's anything but the alt or battery itself. I would pull both and have them tested at a parts store.

Though you changed your voltage regulator, it can still be bad. I had to replace mine twice, but then I read on here about taking it off...so I did.

Listen to Greg, disconnect one load at a time until there is no current coming out of the battery. A good current probe would help a lot: Buy something like a Fluke 80i-110s AC/DC Current Clamp. It can be used for most everything, including house stuff. It won't measure starter current but can be used to test alternators.
You just place it around the battery wire and hook it up to a DVM (and keeping in mind the scale you are on) it will tell you how much current is flowing in a wire. Very handy.

Ron