66 Coronet 383 where is the engine to firewall ground attached

Mine is under the voltage regulator but it may not be stock
Maybe this would get better results in the restoration forum

Thanks Cab

1966 satellite,

right in between ballast resistor and voltage regulator

...and make sure you scrape a little paint off the contact area, to get a good ground.

Thanks everyone where does it attach on the engine side?

Wherever you want it
Or did you mean where is it hooked up in the stock location on the engine?

the further most rearward intake bolt. pass side . Sometimes they will have a separate bolt in a threaded hole just rearward of the intake

Please do not scrape any paint off the firewall.

The grounding happens under the bolt head to the eyelet, and the bolt threads in the hole.

Scraping paint will just cause rust and corrosion, and futur problems.

How many factory body grounds had the paint scraped off? None, and they made it through the warranty and decades beyond without any trouble.