In a semi-recent "Excellence" tech forum, the late Jim Pascha made reference in replys to two readers' questions to adding an extra ground between the engine (block) and the negative battery terminal. This wire, the text goes on to say, was added at the factory beginning in 85.5. Adding it to an early car can allegedly have a positive effect on electrical gremlins. Anybody have any details? Type and size of wire, connections, etc...

 

On my '84, the negative battery cable connected to a bolt on the firewall just inside the battery tray. That bolt actually goes through to the engine side; if you cut away some of the thick plastic lining, you'll find it. The bolt actually stuck through the firewall far enough to get another wire and nut on the other end of it (on the engine side). I bolted the other end of the cable directly to the engine at the back of the cam tower; I just used one of the bolts for the lifting eye.
The size of the wire really doesn't matter, as long as it's at least 6 guage or so. I made my own from 0 guage welding wire (it's a finer strand and more flexible) since that's what I had. You can get suitible pre-made grounding straps (flat braided wire) or round wires at any auto parts store. 8 or 10 inches should be plenty long enough.

Here's the battery side:



Here's the engine side:

 

Thanks, that's just what I was looking for.