They are not grounds, they are the power feed from the alternator to the battery.
The alternator's rated output is 65 amps. Each of the black/orange wires is only
capable of carrying 30 amps. Ford chose two use 2 wires in parallel to get the 65 amp rating.
With this in mind, I recommend that you fix the wiring before you have an electrical fire.
Solder each of the black wires coming from the plug to one of the black/orange wires in the alternator harness.
The alternator's rated output is 65 amps. Each of the black/orange wires is only
capable of carrying 30 amps. Ford chose two use 2 wires in parallel to get the 65 amp rating.
With this in mind, I recommend that you fix the wiring before you have an electrical fire.
Solder each of the black wires coming from the plug to one of the black/orange wires in the alternator harness.
Solder and then cover the splice with heat shrink tubing. It is a high performance car, so do high performance work. If you drive a garbage truck, then do garbage quality work.
See http://fordfuelinjection.com/?p=7 for the right way to solder.
IF you have a real crimp tool designed to crimp the yellow 10 gauge splice connectors, you can crimp the splices on. Smashing them with pliers is not the correct way to do it.
Jrichker is correct about the grounds, but I would like to add to his post.
The 2 Black/Orange wires that are capable of carrying 30 amps each splice together into 1 Black/Orange wire further down the harness. So really they are not sufficent for even a stock 65 AMP alternator in my book.
I would run a new wire from where the 2 splice together to the solenoid with at least an 8 guage wire for the stock 65 AMP alernator, or better yet replace the insufficent 65 AMP alternator with a 130 AMP 3G alternator and run a single 4 gauge wire with an inline fuse or breaker.
The 2 Black/Orange wires that are capable of carrying 30 amps each splice together into 1 Black/Orange wire further down the harness. So really they are not sufficent for even a stock 65 AMP alternator in my book.
I would run a new wire from where the 2 splice together to the solenoid with at least an 8 guage wire for the stock 65 AMP alernator, or better yet replace the insufficent 65 AMP alternator with a 130 AMP 3G alternator and run a single 4 gauge wire with an inline fuse or breaker.