This is the basic 4 gauge common battery cable with two eyelet ends. Note the comments in the pictures and in between the pictures. Also notice I have two different cars, one with a rear mounted battery but the pictures are clearer using one car for some of them. Same principle applies. I don't have them pictured but I have duplicated the block to chassis ground on the passenger side of the engine. I find that engines that are abused or have rough idles tend to shake, twist and so on so on. I check my grounds on oil changes.
This is the power steering bracket. Notice there are two cables grounded here. One goes directly to the battery. The other to the frame rail in the next picture (third picture down)
Frame rail ground.
Notice the SMALL wire coming from the Battery negative and where it leads too. In the last picture I'm using the other Mustang you'll see two wires. One is the EEC Main Harness ground (FACTORY) and this ground which is also factory.
This is your FACTORY EEC Main harness connector for ground.