I always adjust with a vacuum gauge, but I did adjust for high RPM years ago. Whatever works. Order by tool part number. Other carburetors may have a 4 corner idle mix adjustment (4 idle mixture screws). of vacuum is about the best that I can do, but it runs very well. It has been proven you can modify the Quadrajet to flow in excess of 1,000 cfm. Moving the screw down (clockwise) creates a leaner part throttle mixture. Both computer controlled, and non computer carbs. Doesn't anyone know if that tool … This tool has been selected to fit over the APT (adjustable part throttle) screw in the Quadrajets with internal APT. Burroughs J-7292 set for 1958 Pontiac with 2GC $20.00 . These mixture screws were factory set. Idle Air Bleed This is a worthwhile piece to adjust properly too, especially if you have a lot of mods. Carburetor Adjustment Set; 6 of the most common 2 cycle, sma Our streetrod had a 350 SBC with a Rochester Quadrajet carb. Shop for Performance Tool Carburetor Adjustment Set Part #: W1185 for your vehicle. Length, Bits, Kit. Visit our site for coupons and promotions. The Quadrajet has 1 3/32- or 1 7/32-inch primary throttle bores with either 750 or 800 cfm. Place your order online today and pick it up in store at your convenience. Burroughs J-7325 set for 1958 Pontiac with tripower $75.00 . I bought a kit with the proper tool to turn it, and a travel indicator/idle air bleed tool for $4 at Pep Boys (ask for a mixture adjusting kit, listed with the rebuild kits for the carb.) Dealing with a 77' q-jet (from a 350 chevy truck and on a 307 now) that has the APT screw located just forward of the main metering piston. Burroughs J-7400 set for 1958 Buick with 4GC $30.00 . I have seen a slick little tool that fits right in the proper spot to adjust. Adjust this in 1/4 turn increments. Get product details, choose a store, and get directions. Just what exactly does this do? I am in agreement the the Quadrajet carb is a great bit of engineering, as they went on so many different engines with different displacements. The idle circuit adjustment screws have the ends that look like the blade of a screw driver sticking out. The Quadrajet uses a Double "D" carburetor adjusting tool. These are original tools, most used, but in like-new condition. Part Number: MNP-08-0229 Carburetor Adjusting Tool, 90 Degree, Chrome Stainless Steel Driver, Blue Handle, 17 1/2 in. My engine has a mild cam and 15 in. Adjusting a Quadrajet carburetor requires basic knowledge behind the theory and concept of this carburetor. Applications: 2mm double-D - VaraJet lean authority screw & idle air bleed; & DualJet & QuadraJet mixture control adjusting screw 2.5mm hex - DualJet & QuadraJet TPS adjusting screw 7mm double-D - DualJet & QuadraJet main … Remove plug from air horn and adjust your part throttle mixture. These tools adjust various settings on Rochester QuadraJet, DualJet, & VaraJet carburetors on most GM vehicles having the 3C system.Weight: 3 oz. Some carburetors, such as the Quadrajet found in most GM vehicles, have a special screw and require a specific adjusting tool. When I first took the carb apart I had to really work to get it out … In a nutshell, Quadrajet carburetors have different barrel sizes for its 2 primaries and 2 secondaries thus the term Quadrajet.