Amp Meter Issues, Starting, Battery VR ALT.?

[surfsnake2]

1974 260Z Electrial Issues

Hi, about 2 years ago i bought a new alternator with life time guarantee, i also have a 150 watt amp in my car that powers my subwoofer. So what ended up happening is one day the car would start, it was totally drained, and you could hear the starter just barely trying on the first 1 or 2 turns of the key, then nothing, except you could hear the fuel pump running. So we jumped the car, and it worked, and every few times the car wouldnt start, so i replaced the alternator, and it worked fine for about 1 year. a few days ago i had the same problem, and like before, the amp needle is constantly moving, wether i turn on the lights, or have the radio kup all the way or have the volume at 1, which i have never seen it do except for these 2 times, i also replaced the voltage regulator and 2 places tested the battery and said it was perfectly fine. And the reason i replaced the alt, and VR, was because i was having the starting problems again, which now are mostly fixed, although the start feels a bit weaker than usual. And everytime i start the car the amp needle is on the far right about 3/4 of the way, but very quickly goes back to the middle, not like before which was a slow or gradual decline down to the middle. So im out of ideas, New VR, Alt. and battery is in good condition, im not sure what i should do anymore =/? So any help/advice would be great. Although i love to work on my car, im not real good at knowing the names of the car parts, so please use detail or a picture if you know what might be specifically wrong.

P.S.: Dont think this has anything to do with it, but my clock does not work, my temp gauge works about 80% of the time, so could it possibly be a bad meter? although I dont see how that would keep it from starting.

[Zedrally]

Checked the battery terminals? from your PS it sounds like a bad earth connection.

[surfsnake2]

Yes actually, cleaned them just recently, and put new hookups on it for both the positive and negative.