The GM G-body LS swap presents some unique obstacles that are becoming easier to circumvent. The fuel system is one such obstacle that can be nearly a bolt-on project now. The G-body almost lends itself to the fuel system retrofit with all of the current parts available. Some customizing is required with the fuel lines, but still a very straight forward project with the proper tooling.
The LS engine requires a fuel pressure of 58 PSI and most fuel supply lines are an AN6 size. The fuel line shown in the photos was hand formed using stainless steel seemless tubing (purchased locally from Old Dog Street Rods) and stainless steel AN6 fittings (37 degree flare parts purchased from McMaster Carr). There is a need for some type of pressure regulation to make the constant 58 PSI possible. The easiest way, and perhaps the cheapest is to use a C5 corvette filter/regulator (part # WIX 33737 available at NAPA, O’Reily’s, or even Amazon.com). This style filter/regulator will also require adapters for the GM style quick disconnect ends to convert over to AN6 ends (my choice for adapters were Russell 644123, 644113, & 640940). There is a return line required and depending on which style intake determines the length of the return line. Since I am using the car style intake and the corvette style filter/regulator, this return line runs only from the filter back to the tank.
The G-body already has a factory fuel tank that is set up for fuel injection (Turbo Monte Carlo tanks and Buick Grand National / T-type tanks). The sending unit is also a stock application, however, the fuel pump will need to be changed out to keep up with the fuel supply demand. I used the Holley 12-914 fuel pump, which is a 255lph style pump, but others can be used (such as part # F20000169 found on Amazon.com). The fuel return line and the vent line on the sending unit also will need to be changed – see the MalibuRacing.com forum for an in-depth discussion on the sending unit.
Next, an easy way to distribute the fuel to the injectors. Since I chose the FAST 90mm intake, it was very convenient to use a corvette style fuel rail ($20.00 craigslist), but other styles may be used depending on the fuel demands of the engine. When using the truck style coil packs and the truck coil brackets, this style fuel rail will not fit due to the 90 degree bend at the quick disconnect point on the driver’s side. It is worth entertaining the idea of moving the coils to a remote location, or altering the coil bracket, but both options will likely result in a bare stock valve cover (which looks silly in my opinion), or purchasing aftermarket valve covers (which I may do at a later date for aesthetics). I simply removed the 90 degree bend section of the fuel rail and used an aircraft/industrial grade compression fitting from Swagelok to adapt to an AN6 size inlet (part # SS-600-6-6AN).
More of this fuel system can be seen in the book “GM G-Body Performance Projects 1978-1988” by Joe Hinds. As the owner of Bulldawg Muscle Cars, Joe is a great resource for the G-body community. Check out his website and definitely check out his soon to be released book! (Amazon.com)
Lots of things are coming together on the HotRodRegal. Up and coming posts will include new parts, suspension tweaks, all kinds of wires, shiny stuff and hunting more Baer!!!