Dumb question

I have one running from the negative terminal to the block, and I have one running from the block to the chassis...and one running from the head to the chassis.
 
Extra grounds are like the reserve parachute for a sky diver.
If the main one fails, there is always your reserve.

The best plan is to have all the grounds meet at one central spot
and connect together there. That eliminates any voltage drops
from grounds connected at different places