Yes. There are books dedicated to the Rochester Quadrajet.
To adjust the fuel mixture on a Rochester Quadrajet carburetor, locate the mixture screws on each of the primary side throttle bodies. Turn the screws clockwise to lean the mixture and counterclockwise to richen it, making small adjustments while monitoring the engine's performance. Ideally, adjustments should be made with the engine running at idle and using a vacuum gauge or exhaust analyzer for optimal tuning. Always make incremental changes, allowing the engine to stabilize after each adjustment before proceeding.
You can buy a kit with new jets and metering rods for this purpose. Quadrajets can be a little tricky, so you might want to get a how-to book and read up on the procedure.
If it a Rochester carberator, there is no mixture adjustment. That is an internal setting done when the carburetor was put together or at the time of rebuilding. The only adjustments you can make is to the idle and choke I have a 93' 2500 vandura and It failed smog and I advanced the Timing a tiny bit and it passed....yaaaaay
The 1987 El Camino with a 305 V8 engine typically comes equipped with a Rochester Quadrajet carburetor. This four-barrel carburetor is known for its efficiency and ability to adjust to varying engine demands. It features an automatic choke and is designed to provide good performance and fuel economy for the vehicle.
The fuel mixture is controlled by the computer and is not adjustable.
Turn Drivers side fuel mixture screw CW until it Stop turning. (Lightly do not over tighten) Turn Fuel mixture CCW 3 turns then stop. Do the same on passengers side. Start engine Turn mixture screw as before CW until Engine Starts to stumbel then back out 1/4 turn. Do the same on other side. set RPMS ur good 2 go
Computer controlled
If it's an EFI engine you do not adjust the mixture screw. The mixture is computer controlled.
adjust the two fuel screws all the way in and adjust a half turn out until you get it right
torque specs air fuel mixture screw on a yz125 2003
They are to adjust the air/fuel mixture.