I've tried various combinations, and can't assign Z to pins 16 17 successfully, which is my controller's A axis.

The board I have is XYA so I'd like to find a way to assign G-code Z to that A port on pins 16/17 on the board.

Just set up your Z axis for pins 16 and 17. That's it. If it's not working, something else is wrong.

Can you post any info on the board you have?

I think the board is a toshiba 6560 hqv3-t3

I can get XYA to work, but when trying to assign Z to the A's pins, Z doesn't work.

I tried sharing the pin numbers too, Z & A using pins 16/17 but only A would work.

I tried mach3 mill, and none of the motors work,
then tried mach3 plasma, and everything works except Z.

I even tried disabling A in ports & pins setup handing Z the controller's A's pin numbers, but no go.

Else, I could just write a VB program to change Z's in g-code files to A's.
I'm very sure that type of program would be usefu to everyone. Changing any letter to another so you don't have to keep swapping out motor connections.

Does mach3 plasma not use Z?

I am having trouble using pins 1,14,16 and 17 as output pins myself. One thing i learned is that there are 2 different printer port settings in BIOS for some computers. SPP or standard printer port or ECP for enhanced printer port.

 Looking at the wiki for the parallel port there are some differences between these two settings. i have no idea if this has anything to do with it or not? I need to try both of these on my own machine and see if it makes a difference. but it is an easy thing to try.

on some computers i have trouble using pin 1, if not in EPP setting for the printer port

I am thinking each version works differently. In the end after all the others failed, I made a blank profile called Lathe and coded in all the pin info.

ALL of the other default settings like Plasma, Mill would not work even when all of the pin info was entered. The Mill and Plasma also messes around with your motor setup. Z becomes A, X becomes Y and Y axis on your controller becomes X.

Its messed up, they should fix it. It took me 2 full days to get the program to work properly, and I had to make a blank profile. All the others kept overriding my settings and would not comprehend my pin settings.