Recently bought a 73 240z, pretty stock setup but on a L28. I bought it knowing it had charging problems, but didn't think anything of it. Well it came with 4 alternators, all bad. So i decided to do the 280zx 60 amp upgrade. Finished it and when i hook up my multimeter to the battery it's jumping around pretty bad. I also have tried taking the negative off the battery and the car will die. I had the alternator checked and it came out good. Im lost on what to do. I think i'll just start chasing wires tomorrow to see what I find, but I was wanting to know if anyone else has had this problem and would know where to start. Thanks, Casey