1966 c10/Suburban Where were the factory grounds?

[bloo]

On my 1966 c10 Suburban, I have a negative battery cable with the starter cable running down to the block, and a small wire running to the core support. That is all I can find.

I don't think my frame is grounded, except by accident. Was it when the rig was new?

I dug through a bunch of old threads, here and on other sites, and the results were conflicting. I guess the grounding was different if you had a factory radio? I have seen pictures of straps from the frame to the front (firewall) body mounts, and straps from the firewall to the v8 valve covers, sometimes on both sides. So far I have found no evidence of any of that on my truck.

How did the gas tank ground? Did they just depend on the strap to do it?

I am interested in knowing how it was done on trucks as well as suburbans.

Thanks!