It is an undisputed fact that the popularity of the '55-57 Shoebox will never die. Even within our publication there have been many articles on just about every aspect of restoration and modification of these vehicles. While there are countless engine, drivetrain, and suspension options available, there has not been much attention paid to the update of the entire electrical system. Unfortunately, all the performance mods in the world won't make any difference when the tired old wiring in your car can't handle the power requirements of all the electrical accessories so popular on these vehicles.
Original replacement wiring harnesses for '55-57 Chevys have been available for many years. While they are excellent products that are true to original engineering specifications, they leave something to be desired in circuit protection and expandability to custom accessories and performance products requiring connection to the fuse panel. Original wiring harness specifications in the '55-57 vehicles were really very basic. There were no electrical options to speak of and those that were available from the factory, such as power windows and power seats, appeared on very few production cars. Take a look at an original fuse panel in any '55-57 vehicle and you will begin to see the problem.
The panel is small with minimum fuse protection. In many cases, age has been unkind to the panel and the original glass fuse clips are rusted to the point that continuity is lacking. Add to this the fact that there is no room for expansion. Besides, even if there was room, the major power feed wires to the fuse panel are too small in gauge to handle the additional power requirements demanded by modified vehicles. The bottom line is that the electrical system design needs a major overhaul.
We contacted American Autowire/Factory-Fit when we heard about their new Classic Update Series wiring kits designed specifically for '55-57 cars. We were familiar with their Factory-Fit product line of reproduction wiring harnesses and wanted to see what this new kit had in store for us.
After close examination, we realized that this was not a generic rewire kit. It is a well thought out kit that includes everything you need to rewire your entire car. Important pieces such as taillight connectors and parking light sockets are included along with their respective weather tight tube and grommet assemblies. However, the best thing about this kit is that knowledge gained in years of producing replacement harnesses is reflected in the design of these kits. The mounting of the fuse box and routing of the wire under the dash has been thought out to be a bolt in exercise that uses existing production routing wherever possible. On the other hand, under hood wiring is completely flexible to allow custom wiring routing (hiding) for a clean look.
All this is great stuff. But what about the kit's ability to handle all the cool stuff we like in a modified car. We tested this by laying out requirements for installing the kit in a '57 car to be equipped with A/C, a Dakota Digital dash cluster, and RAINGEAR(r) under dash wiper system. Added to this was our desire for future addition of power windows, power seats, cruise control, and an electric fuel pump. We did not think this wish list was too much to ask. Filling this bill turned out to be an easy task as provisions for all these requirements are designed into the kit.
The first step in installation was to become familiar with the installation instructions. The "cook book" approach covers installation of the kit in four major groups: under dash, rear body, instrument cluster, and front light and engine wiring. Full schematics are included for the entire car as well as specific installation instructions for each of the four major groups. We removed the seats as this will save considerable time in wiring the body. Other than putting our bodies in those uncomfortable under dash positions, the installation went exactly as shown in the instructions. We now have a high-power electrical system that incorporates modern safety features and expandable power capability for the future.
Headlight switch connection is a plug-in for the included headlight switch.
The instrument cluster was removed in order to see how the harness components are routed. The original harness clips across the upper dash are used as well as clear space along the firewall.
Passenger side wiring continues using stock mounting clips across the upper dash area. Notice the wiring for the ignition switch and the steering column as it lays in the correct position from the firewall extension. Wire placement was designed to avoid interference with under dash cabling and mechanical components. Wiring for the engine compartment is coiled at the firewall. The stock engine harness hole was closed for a smooth firewall appearance. This is no problem as the kit includes more than enough wire to handle the custom routing required for this installation.
Rear body harness plugs into the under dash harness and is retained by body clips in the upper kick panel. Retention clips below the threshold plate are used for routing to the taillights.
Rear body retention clips are used to continue connection to the taillights. Correct original light sockets and tube and grommet assemblies are included in the kit. Even in custom applications, these are a necessity.
Completed rear body harness includes connections for license plate lights and a third brake light.
Stock 1957 dash instrument cluster.
Stock '57 dash instrument cluster was wired to use the cluster disconnect feature of the kit. Installation and connection to the under dash harness now becomes an easy plug-in.
Dakota Digital dash instruments are also easy with the dash disconnect feature. Here the control box is pre-wired for an easy mount and connection to the under dash harness.
Completed installation of the Dakota Digital control box and connection to under dash harness in driver kick panel. Connector in the kick panel cavity is the accessory power feed connector for power windows, power seats, power door locks, cruise control, and electric fuel pump. Also shown is the door jamb switch connection for the overhead dome light.
Design of kit also allows for custom update features such as the RAINGEAR(r) under dash wiper system. Clearance for the wiper motor is no problem.
Front light harness wiring is completely flexible with enough wire for any custom routing plan. Stock front light connection is hidden behind the air inlet chamber. We chose the stock harness routing for this installation.
Alternator connection uses heavy 8-gauge wire and includes protective boot. Connections for internal regulator and one-wire alternators are included in the kit.
Correct light sockets and boot assemblies are included for the parking light bar connections. Stock routing clips are used here but any custom routing plan can be used.