The Street Avenger series of Holley carburetors comes in 670- and 770-CFM (cubic feet per minute) airflow models. The series is equipped with a 4-barrel, vacuum secondary design that can be mounted on a square or spread bore intake manifold. A double pumper, the Street Avenger will require tuning on both the primary and secondary components, including the fuel float valve, metering block idle adjustment screws and pump diaphragm arms.
Slide a 15 thousandths clearance file between the arm and the arm adjustment screw to check the setting of both the front and rear pump arms. Ensure that the arms are pushed down slightly while the file is inserted, indicating a correct setting.
Adjust the arm adjustment screw down if it is not touching the arm while in idle position.
Adjust the arm adjustment screw up if it overly engages the pump arm. The arm should barely touch the adjustment nut at idle.
Locate the screw on each side of both the primary and secondary metering blocks. Screw them tight, or until they bottom out, and back them out exactly 1.5 turns.
Attach a vacuum gauge to the vacuum port on the top of the intake manifold. This port is designed for diagnostics and should be easily accessible.
Start the car and allow the engine to idle, adjusting the primary idle screws in equal increments while watching the vacuum gauge, then moving the secondaries to repeat. Continue adjusting both sets of screws until the vacuum gauge reaches its highest reading.
View the sight window on the side of the Avenger to establish the level of fuel within the primary and secondary bowls. If the level is below the window, or above the base of the window, a float valve adjustment is needed.
Turn the adjustment screw on the top of the bowls, two turns. Pry up on the adjustment nut to break its seal from the fuel bowl and start the car.
Turn the adjustment nut down to lower the fuel level or higher (counterclockwise) to raise the fuel level until it reaches the base of the sight window.
Tighten the float adjustment screw while keeping the adjustment nut still. Do this for both the primary and secondary bowls.
