Holley EFI install

Time to replace the carburetor with a new Holley Sniper EFI complete system. Pulled out the mechanical fuel pump, carburetor, all metal and rubber fuel lines, and the fuel tank. Kept the HEI distributor in place for the initial startup, as recommended.

Decided to go a returnless fuel system by using the Holley #12-303 OE style in-tank fuel pump/regulator/sender module. This system needs only one fuel line from tank to engine, with no return line. Installation required the tank and sender unit to be removed. Installation of the new unit was simple. Bench tested the fuel sender to verify resistance at empty and full levels, but found the sender float arm would hit the pump, so I had to bend the arm slightly outward. Install needed only a few minutes to carefully push the hydramat through the sender hole. Paused halfway in to mount the fuel level sender using the two screws. Wiring was plenty long enough to reach the rear of the fuel tank and meet with the tan factory sender plug.

Removed the 50 year old factory metal fuel lines from inside the frame, which were rusted and near failure.

Most of the total install time was spent installing a new Right Stuff #CGL7030S stainless steel fuel line inside the car frame from the fuel tank to the engine. Only a short length of Earl's Vaporguard 3/8" fuel line was needed between the tank and hard line. Mounted the 10 micron fuel filter forward of the engine below the alternator. Fuel line into the EFI unit into position 1 at the rear near the throttle cable. Did not want any hoses out of the front of the EFI unit. Had to purchase a plug to seal off the EFI unit pressure regulated output which would not be used, used the Earl's AT581406.

Installation was fairly simple, with only two sensors, a water temp sensor in the intake or the cylinder head, and the wideband oxygen sensor in the exhaust. My engine already had an O2 sensor in the driver side exhaust and a temp sensor in the driver side head, both feeding dash gauges. I left those alone and installed the Sniper senders in new locations. The water temp sender went into the large boss in the Edelbrock Performer intake using a large male 1/2-14 NPT, small female 3/8-18 NPT brass adapter.

Oxygen sensor location was chosen on the passenger side exhaust on the header just before the collector. Had to remove spark plugs and the header to drill a hole and MIG weld on a sensor bung, rather than use the kit clamp-on fitting that was too small to fit the 3-inch collector. Installed the header on the engine, then the sensor in the exhaust, routing the wires away from hot pipes, using clamps to other locations.

Wiring to the base unit was pretty simple, two wires to the battery posts, one to a switched power source, and one wire to the HEI unit tach output.

Retained the working HEI distributor for the first startup until tuning was complete.

Next post will have results of the first system startup and the tuning process.