Problem: Battery discharges with 2 different gauge swaps.
Have a 1982 carbed 350 CI with oil pressure and water temp sensors on the block, no computer.

No battery charging problems with stock idiot light gauge pods.
Oil and water were wired to Summit gauges.

1. Replaced idiot lights with 4 Monte Carlo gauges (gas, oil, water, volts).
No tach or clock at all in gauge cluster.
The gas gauge plugged into the circuit board connection.
Wired oil and water gauges to each sensor on the block.
Wired the volt gauge to 12 volt keyed source.
Problem: battery discharged within 2 days of driving.

2. Went back to original idiot lights 2 weeks ago and everything was fine.
The alternator is good, if the battery maintaining charge.
Had alternator checked anyway at Autozone and it was fine.

3. Just replaced the stock gauge pod with an entirely different Monte Carlo gauge pod/cluster (tach, gas, volts, water, oil) with Monte Carlo printed circuit.
Wired tach coil lead to HEI distributor (tach works).
Wired oil and water gauges to their sensors. Cut each wire at the printed circuit harness and ran a wire from the circuit board end of the cut wire to each sensor. (oil and water gauges work)
Gas gauge and volts were plugged into their circuit board connections (each gauge works).
Problem: battery discharged within 2 days of driving.

Has anyone else had this problem when replacing idiot lights with Monte Carlo gauges or have any suggestions regarding the source of battery drain?
Thanks for any input

The exciter voltage for the alternator is run through the gen (idiot) light. When you change to the gauges you are eliminating the exciter voltage (brown wire at the alternator) so the alternator is not working and in two days the battery is dead.
With the gauges installed check the voltage at the battery when running. It should be in the 13.5 to 14.7V range with no lights or AC on.
Do some reading here and it might help you get the thing working.
http://www.madelectrical.com/electricaltech/remotevoltagesensing.shtml
Let us know if you figure it out or need more help.

Thanks for the link. By eliminating the brown wire at the dash, there is no 12 volt source to activate the alternator.
The white plastic connector on the back of the alternator has 1 red wire and a thinner black wire.

Should I cut the black wire and run the alternator end of that wire to a switched/keyed 12 volt source to provide the voltage so the battery will charge?
That's the best I could understand the information and other posts.
Please let me know if that was the fix, thanks!

That should fix it. The yellow wire at the wiper switch is an easy place under the hood to pick up the switched voltage.

Thanks for all your help. The wiper is a good source, since it's not used all the time.

glad to see you in the "busy beaver" mode there lindsay:nanawrench:sorry bout the delay on the front sway bar,been in the same mode,lol.nehoo ill try and get it out soon.