first u might look at the bat on the left side (drivers side, if u remove all that styrofoam u can weld in the factory batt tray & tie down) I did use that as my ground also added ground straps going forward to the ground under engine left side .
I used a 1/2" dia stranded cable , right near the fuse flap you know that little one next to the water tank I added a hot post with batt and other small things and my rear batt cable
I ran it down the front r side wheel well cover into car(there are already holes there then under the carpet (without removing carpet) down the inside of the door Covered by the door sill
Lifted up the carpit goinh over the rear tire hump (there is an opening in the corner next to the gas ) into the trunk cable on right side ,,,under the tail lights to the batt ,,already have my ground welded in connected positive, then my ground FIRED IT UP that was my set up for 12 years in my first V8 I did use a 900cca batt. jim
NOTE run cable front to back not from back to front