my early 280z uses the ammeter which I prefer to a voltmeter, anyway the problem is its not center when no current is being drawn. I was wondering if anyone knows off hand if there is a centering adjustment mechanical I would presume.

It's probably the same part number as for the 260Z. When I had one of those apart, I did not notice a mechanical adjustment, but I wasn't looking closely at it. It's not too difficult to remove, open the case, and inspect if you want to, provided you don't have factory AC in the car.

Dave I looked and looked, I can’t find either one. 

have AC, so would like to know before I pull it out. since it has to return to center I assume it has to have some kind of spiral spring that hopefully has an adj.

Edited May 21, 20188 yr by Dave WM

I could look at another spare gauge, but that won't be until next weekend at the earliest.

that would be great, I am in no big hurry, just would like to fix it if fixable.