The Holley 1050 carburetor is designed for drag racing. Its 1050 CFM (cubic feet per minute) air flow rating makes it ideal for large-block, high-horsepower gasoline engines. The 1050 has a 3-circuit metering system for enhanced tuning capability, notched floats and extended jets for high-G starts, and dual 50-cc pumps for a maximum fuel delivery compared to the stock 30-cc pumps found on most Holley carburetors.
Unscrew the sight port screw on the side of the fuel bowl.
Place the vehicle on level ground and rock it from side to side while watching for a light trickle from the sight port hole. If fuel pours out, or refuses to come out at all, float tuning will be needed.
Start the engine. Adjust the float valve screw two turns counterclockwise. Pry up on the adjustment nut. Use a wrench to turn the adjustment nut clockwise to lower the float or counterclockwise to raise the float.
Watch the sight port hole until fuel trickles out. Tighten the adjustment screw while keeping the adjustment nut still. Reinstall the sight port plug screw.
Locate the idle mix screws on the sides of both the primary and secondary metering blocks (these blocks attach to the center choke tower, forward and rearward). Tighten each screw, then back them out 1.5 turns to create a base point for the adjustment process.
Attach a vacuum gauge to the intake manifold service port.
Start the engine and allow it to idle. Adjust each screw on the primary metering block in equal 1/2-turn increments.
Watch the vacuum gauge as it reacts to the screw adjustments. When the vacuum level reaches a maximum (meaning it doesn't increase when the idle screws are turned) this indicates that maximum vacuum has been achieved. Move the secondary metering block and repeat this adjustment process until the engine idles smoothly.
