If you have a lot of electronics, especially EFI, you need to do some research and avoid creating what is known as a "ground loop." Essentially, this is a situation where current flowing in that circuit can cause a voltage drop which can adversely affect other circuits.
Back in the day, I simply grounded the battery to the trunk floor with the ground cable "split" into 2 eyes for more contact.
Then a large gauge cable from the engine block to the front frame horn this worked well back then, this was a 10+:1 compression 440
I guess most nowadays advocate running a SEPARATE ground cable all the way from the batt NEG to the engine block, then using that as a central ground point.
