Fuel Level and Pressure Monitoring: Sending units for fuel level are available from many aftermarket suppliers. Ours came from Classic Instruments, which made our gauges, and is a straight-forward installation following their instructions. Basically, you have to cut the length of the unit to work with the depth of the tank, cut the float arm to length, and make the electrical connections for power and ground.We also like to monitor the fuel pressure, so we mounted a fuel-pressure gauge in the dash. Since you can't run a fuel line into the passenger compartment, this one uses an electric sending unit that we installed at the end of the hard fuel supply line. Photo 16 shows the location of the sending unit.
Line Routing/Fuel Filtering and Pressure Regulating: With the LS series engines, and any fuel-injected engine that we know of, you'll need both a supply and return line. Most systems we have seen have used a 3?8-inch supply line and a 5?16-inch return line. Some builders run both lines from the tank along the frame to the engine. Another popular approach, and the one we used, is to use the C5/C6-style fuel filter. This has two advantages: It has a built-in fuel pressure regulator, and it allows the use of a shorter return line to the tank if mounted toward the rear of the car. Finding a good location for the fuel filter needs to be done before routing the lines from the tank to the filter and from the filter to the main hard line running to the engine. We searched for a location that would be clear of heat sources, allow for a straightforward approach to route the lines to clear the body, and provide easy access for service. Well, achieving all three wasn't exactly as straightforward as we had hoped. While two of the three objectives were relatively easy, gaining easy access in the best location we could find wasn't as simple. We ended up locating the filter along the rear of the passenger-side inner framerail close to the tank. That made for a short distance for both the supply and return braided lines between the tank and the filter, and also provided a good route for running the supply line along the frame to the engine. Gaining easy access for servicing though wasn't as easy. We ended up making a small door in the rear compartment to get at the filter, and that solved the problem. Photo 17 shows the location of the fuel filter and the supply and return lines from the tank.
We used braided stainless lines and AN fittings for the lines between the tank and filter, and a hard stainless line for the run along the frame to the engine. Using a braided line for the supply line along the frame is not recommended as most hose manufacturers will warn against using lines over twelve feet in length. One tip that can help in bending the hard line to the shape you need is to first use a length of 3?8-inch copper tubing to make a template. Copper is easy to bend and should give you a good idea of the best route and bends you need to make. Bending stainless tubing is more difficult, but with a little practice first and a good tubing bender, it can be done well. We wanted one continuous line with no additional connectors, which made it a little more involved, but with a second pair of hands and eyes, it worked out well. We used billet aluminum clamps to mount the line along the frame and Swagelok compression fittings at the fuel filter. Photo 17 also shows the route we took for the hard line along the rear of the frame; photo 18 shows the line running along the main framerail toward the engine. From the end of the main fuel line, we used a braided stainless setup from Street & Performance, which connects to the fuel-rail fitting using a Swagelok fitting (Photo 19).
Engine Wiring Harness & Computer:What once seemed like a daunting task is now made relatively easy by using an aftermarket engine wiring harness along with a reprogrammed computer. These provide for all the necessary connections, as well as the reprogrammed ECU that eliminates all the unnecessary programs contained in the stock ECU program.Sources: There are many sources for the LS engine wiring harness these days. They come with the right plugs for making the connections, the ECU, and the programming needed. For this project, we used components from Speartech that did a super job on the harness. When ordering the harness, you should have a good idea of where you want to mount the ECU as that will determine the length of harness that will fit best. Some common locations for mounting are in the engine compartment, under the dash, or even in the trunk. Deciding on the placement and taking measurements of the length you will need at this point will make the installation neater and avoid unnecessary routing of any excess harness.