Maybe looking in the wrong place for starters...
I set mine up by finding the approx. 10 ga switched power wire coming from the bulkhead connector area to the old electronic ignition brain on the driver side fenderwell.
Cut that wire away from the brain box, grafted it to 10ga all the way to the hot wire of the new distributer. Having a 3 wire connector on the HEI, one is hot, the other is ground, the other is tach...
I didn't use a summit hei though.. Bought a generic gm style off of amazon. I did however switch over my distributer gear to the new distributer.