Valve seat mounted the pump to the underside of the floor

Posted by zjautopartsLee on January 12th, 2016

The EGR valve spindle has four 80lb/hr fuel injectors already installed, two each on what would be the “primary” and “secondary” sides of a carburetor. Also visible here in the throttle bores (note the tiny holes around the bore) are the patent-pending annular discharge fuel rings. According to Holley, these are for maximum flow and atomization, and because the injectors fire right into these passages, there are no delays as with a carburetor booster venturi.

Can you remove and install a carburetor? Then you can install the Holley throttle body. We used an inexpensive 1-inch spacer between the throttle body and Edelbrock intake, which proved to be an issue (see later in story).

Electronic fuel injection works with much higher fuel pressure than a carburetor (40-ish psi compared to the carb’s 5 to 6 psi), so you must use an entirely new fuel system. Holley has complete fuel-system kits, some even packaged with the EFI system. The company offers a lot of options for both, depending on your application. We chose the Dominator inline pump and regulator.

The fuel system requires a return line from the regulator back to the tank, so we modified a new stock fuel tank for a -10 feed line (in the stock flange) and an -8 return, which required a bung welded into the tank. Don’t do this with a used tank unless you know what you’re doing, or I predict a big, painful bang in your future. It’s why we started with a new tank that never had fuel in it before.

Valve seat mounted the pump to the underside of the floor, on the passenger side next to the subframe connector. Note, you must also make custom-length fuel hoses, which are included in Holley’s fuel system kits.