My 1984 gt350 willnt stay running or start

The voltage regulater mybe bad ! It maybe inside the alternater! So you may need a new alternater! Take it to auto zone and they Will check it!

newer chevy clusters are known to be buggy, sounds like a short in your cluster.

Was the PCM checked for troubles codes? If so, what were they?

Check the alternator drive belt adjustment 2- Check battery terminals for corrotion or loose.3- loose,broken or faulty wiring in the charging system. 4- short in the vehicle wiring cause continuous drain of charge., sammyc47

You need to measure the charging voltage and current using a multimeter while Rev'ing the engine. If there is no clean flow to the battery then you need to start from the alternator, the output ac and the charging regulator section which rectifies and controls the charging. The alternator can be taken out and checked individually , if there is a steady AC flow. Check the battery ground and also the charging regulator which is usually an extra unit- trace the lines of the alternator to this unit.
Please find some tips below .

http://www.fixya.com/cars/r5824824-draining_car_battery_charge

sounds like your alternator is not charging the battery. with vehicle running take measure the voltage of the battery f it is higher then 13volts it is charging. if you do not have a volt meter remove the ground cable while the vehicle is running and the vehicle should stay running.

Color codes are shown in the diagram. The terminals should be marked F (field), S (stator), and B (battery) on the alternator. The ECM provides the stator current. Please let me know if you have more questions.

sounds like your alternater is not fixed. Your car ran off of battery power till you drained it. Complete alternater repair and charge battery. You can check if your alternater works by starting car and disconnect positive cable if it stays running your alternate is fixed. Shut car off and replace positive cable.

If the vehicle stalls when you pull the battery cable loose from the battery the alternator can not be good because the car would stay running. You have an issue with the charging system, Possible voltage regulator which is in the alternator. Have the alternator taken of the van and tested a the parts house.

First tell me why you don't think it's charging.
Because of the voltage reading you are getting at the battery terminals? The range you want is between 13.6v to 14.2v. The higher the voltage the lower the amps. and true the other way, the lower the voltage the higher the amps. If you get a reading of 13.6v or lower, the alt is nearing or at max output. An alt can only run at maximum for around fifteen minutes and it will start slinging solder from overheating. It's a good indication the battery is either totally dead or junk. Charging above 14.2 the alternater is running wide open and is only putting out high volts which will cause the battery to boil , in turn destroying it. This is a bad alternater. All alternaters have integrated voltage regulater with the exception of ver few of the earlier ones. You cannot test an alternater by removing a battery cable to see if the engine keeps running without taking great risk of damaging the alt, regulator. So tell me why you feel it isn't charging. Remember an alt is not made to charge dead batteries. Their sole function is to maintain the battery charge. Without a battery, the alt won't last 10 seconds.
Hope to hear from you and good luck.