72 Suburban engine harness help

[Franks 72]

I tried this post in electrical but no takers. Can someone look at the engine bay harness which runs along the firewall and exits into the bay on passenger side. Wires in harness are heavy gauge pink, brown-white stripe,blue,green white stripe and the black I need info on. Putting engine back in I find the black wire in the engine harness which I forgot to mark. It is in a small bundle which contains the pink solenoid wire for carb .
It appears that I was using it (ring terminal) but does not appear to be a ground (9.3 m ohms)and does not come to the firewall bulkhead connector. Any help would be appreciated.