chevy style HEI on 318

What ignition system do you have right now? If you already have Mopar Electronic Ignition you can easily hook up HEI to your stock Mopar distributor.
If you have points, just get a standard/stock Mopar electronic ignition distributor (2 wire, no lean burn crap) and hook it up. There's lots of how-to articles on this. Modules and e-coils are readily available.

GMHEISchematic.jpg