dead battery, rough ldle

[meatsauce]

my 88' 62 was running just fine until one day last week the battery was dead when i went to start it. the battery is a yellow top and its been in there maybe a couple of years. i took the bat to advanced for a charge and test. charge and test good. i put it in yesterday at about 1:00pm. i go to start it today at about noon and nothing, no lights on the dash, nothing. took the bat back to advanced, charged and test ok. put the bat back in the truck to start the hunt. turn the key, no charge light, but the truck starts and is running ok. i removed the bat to check that the alternator is ok, truck keeps running but idles rough at around 600 or so. i did replace the plugs yesterday with some basic NGK's. the gap on the package says .032.
i worked the throttle to hear if the alt was making any weird noises. what i heard was that when you let the throttle off there is a grinding sound, its real light and it sound like its coming from the front of the eng somewhere. its hard to narrow it down. after a couple of those the eng idle becomes more rough and the eng eventually cuts out.
i reconnected the bat to start it again and no charge light. eng starts but is running very rough (slightly surging), below 600 rpms, and the charge and check eng lights are flashing in unison and the eng cuts out. where do i start?

forgot to mention, the only things to of changed is that i put a bulb in the left rear marker light and i pulled the front two marker lights that were never installed and just hanging there busted up.

 

[cruiser88]

You can mess up the diode in the alt. if you do that to much....i mean if you unplug the battery while running. Use a meter to verify if it is the battery,alt. Now also check the fusible link and the white wire going to the alt itself from the battery.

Check for voltage at the battery without it running

check the voltage at the battery while its running(should be a slight increase)

Take your meter and find the white wire at the back of the alt.....it should be 13.5 to 14.5 volts or so(best voltage is around 14.5) running of course. you can see if there is 12 volts there even without the car running.

also you say you have a noise. Take the alt belt off..spin the pulley and see how smooth it feels....i have a feeling these two problems are related.

 

[meatsauce]

i'll hit it with the muti-meter in the morning and see what see reads and check the alt without the belt. thanks for the help

 

[meatsauce]

checked the alt

i am getting 12v at the alt not running. while running at idle i'm getting 12.9. at 1,000rpm i'm getting 14v which is the best i can get regardless of the rpm's. my multi-meter stops at 10a so i can not check to see what that number is.
the rough idle to wasn't to bad today while i was checking things. i did put the fuel pulsation dampner screw back in. that might be causing the unusual idle.
where exactly are the fusable links and how do you check them?
i haven't taken the belts off to double check the light grinding noise.
now what do i check? i've pritty much have done what the FSM says.