Ballast, Blaster II, ohms, current, friggin volts!

I prefer the 8-pin HEI to the older 4-pin because it is simpler, more rugged wiring. A factory cable runs from the module to the GM external coil, using sealed connectors, so grab all that and done there, plus you get a tach output wire. Snip off the GM connector for the pickup and you have a rugged connection to your Mopar distributor after you solder & heat shrink the wires (twist them and connect the right way - 50% chance). The "limp home" mode is not a problem, it just gives no advance unless a computer commands it (so ready for that). Your Mopar distributor can handle the advance as normal.

Re computer, the Holley Commander 950 can control the 8-pin module. There was a link posted by TrailBeast about a new, and maybe inexpensive, ignition-only controller called Rabid Gator, but maybe it never went production.

I don't think timing wander is a big problem if you have a good timing chain. I am more bothered by the clumsiness of jumping a spark thru air, even though it has worked since the 1800's. The easiest way to go distributor-less is using the Ford EDIS system, which many megasquirters use. I installed a 36-1 tooth wheel on my Dart's crank pulley for that and a pickup (not using yet). Normally it is a "wasted spark" system, but I am contemplating using a Magnum cam sensor (part of distributor) with a home-made logic circuit to trigger only on the compression stroke and fire a GM LS coil (1 per cyl). My day job keeps getting in the way of such fun.