those work fine and can be used in a vice as well.
if you have a gm distributor that is fairly big around at the wire towers then in is likely an hei. it should get battery power through a 12 ga wire when the key is in start or run position. these run best with 14 volts. if the wiring set you have was for a points truck then use a different set of wires, probably custom made by you, to supply voltage to the coil. the points vehicles had 2 wires that fed the coil, one was battery voltage to start the truck, the other was ballast resistor voltage, usually about 9v, to run the truck. these wires are also too small to run voltage to the hEI unit. the HEI coil wire was usually a pink kinda color and will plug into the distributor on the rearmost terminal of the plug closest to the outside of the plug in bock. the other one is for the tach and doesn't need to have a wire in the plug.check the video below for a better explanation.
here is a link to a video showing the HEI wiring
https://www.youtube.com/watch?v=5us-Zv1vbcc
here is a pic of an HEI unit.
https://www.amazon.ca/ACDelco-934408...40622144&psc=1