We had planned to perform this installation in the Mustang's home garage, but it has been resting at Crazy Horse Racing in South Amboy, New Jersey, awaiting its new custom rear axle assembly. The author performed the install at Crazy Horse, along with the help of proprietor Chris Winter. Having a helping hand when performing this type of install is a plus, but not necessary. Just make sure your plans are firm and that you have enough wire to get the job done.
In Part 1, we've handled the planning, wiring, and a portion of the installation. In Part 2, we'll wrap up the installation and talk about the tuning that is involved when using amplifiers with crossovers, and what can be accomplished by utilizing the signal proces-sing in Sony's CDX-M8800 head unit.
 The factory speakers are next....  The factory speakers are next. This is one of the rear 6x8 speakers that is easily removed after taking out the four screws holding the cover on, and then removing the four screws that hold the speaker to the grill cover. Our '90 Mustang didn't come equipped with door speakers, so there weren't any to remove. We won't be using the factory 3.5-inch units in the dash, so they can stay. |  Our Mustang already had an...  Our Mustang already had an aftermarket receiver, which made it a cinch to remove. It also provided us with the console panel that replaces the factory head unit. If you still have the factory receiver, you can insert a metal coat hanger into the release holes to pop out the unit. You can usually get the proper tool from your local stereo shop, though. |  With our stock components...  With our stock components removed, we installed the 4ga power cable through the grommet on the passenger side of the engine compartment. This grommet also houses the main wiring harness, so use caution when making your pilot hole in the grommet for the new cable. We routed the power cable down in front of the A-pillar and then down beneath the passenger-side carpet along the rocker panel. Our Mustang is equipped with a ProCharger supercharger that relocates the battery to the passenger side. |
 We installed the new Optima...  We installed the new Optima Yellow Top battery and ran the power cable around the front. Then we unsheathed the cable and installed the brass terminal end to connect it to the battery. Our Optima came with both top and side mounts, which gave us a separate positive feed for the power cable. |  Due to the size of the power...  Due to the size of the power cable, we chose to run it up and over the rear tire well. This also put it in a good spot where we could mount the inline fuse holder and distribution block. |  With the fuse holder's location...  With the fuse holder's location established, we cut the power cable and installed the fuse end cap, rubber O-ring, and terminal. |
 The fuse is a monster 150-amp...  The fuse is a monster 150-amp unit and separates the battery current from the distribution block. |  The other end of the fuse...  The other end of the fuse holder goes together in the same manner. Now we only have to cut the power cable's length to reach from the fuse holder to the distribution block. |  The distribution block requires...  The distribution block requires running only one main power cable through the car. Then you can distribute the power to four separate destinations using smaller gauge cable. The same goes for the ground wiring. |