As the distributor turns

You didn't explain what HEI you are going back to. Any existing wiring for that? Photos? Always helps to describe something about your car - Mopar, A-body, year, engine?

Many posts, but most show a 4-pin HEI module. 8-pin HEI & coil is simplest, which is what TrailBeast sells, or can pull at any junkyard from 85-95 GM V-8 trucks. If you have a SB, BB, or RB engine, you can buy a new ready-to-run HEI distributor ($45-70 ebay), which is real easy. Many posts.