i recently bought a 87 z28 305 tpi. i keep popping diods in the alternators. im on my 3rd one now and just killed that one. The harness that plugs into the alternator has 3 teminals in it and the alternators i keep getting have 4. wondering if this is the right alternator or what? how many amp alternator am i supposed to have? and y does this thing keep popping diods?