HEI coil question

Sounds like you have just the coil shown below. I recommend getting your first parts at the junkyard. You would then have the factory cable shown from the 8-pin module to coil, plus the other connectors. Below shows the wiring. For more info, search the megasquirt site, which is where I found my info.

Re polarity of the Mopar pickup, you will have to try both to see which gives a more correct and steady timing. I haven't run the HEI setup on my slant yet, but will post when I figure it out. Twist the wires from the distributor to minimize cross-talk. Don't jury-rig spade lugs to the coil input, just snip the coil connector and wires from a GM distributor.

Re the 2nd Metripak connector, that is for optional computer control of timing. If you don't use it (unconnected) it runs with a fixed timing (limp home mode). GM mechanics routinely disconnect it during tune-ups. Holley's Commander 950 can connect to it. Of course, your Mopar distributor can control timing with its weights and vacuum module.