Your machine has 2.9 ampere rated 6 wire stepper motors. They were
originally run in unipolar mode, hence the 6 wire connection. They can
be run by the PMDX-340 as bi-polar motors by going full winding (series)
or by going half winding. Series offers slightly more torque. Half winding
offers slightly more speed. Or if you determine that you want both you
could upgrade to modern square frame bi-polar stepper motors.
The spindle appears to have had a separate power driver board that
used a manual potentiometer to set the speed and the control box
had a switched AC outlet to turn it on and off. The PMDX-340 likewise
has a switched outlet and should be able to control it in the same
fashion. CNC control over the speed would require more work and
having documentation for the power driver for the spindle.
To run Mach3 using a parallel port you will need a computer running a
32 bit version of Windows7 or WinXP. A 64 bit version of Windows, or
any Win8 or Win10 system will not be able to work with a parallel port
You can also use Mach4 along with our PMDX-411 to run this machine
under and any WindowsXP or later operating system using a USB port.