A single body passage (single venturi) carburetor main body design that offers improved control of the fuel delivery on both the opposing and opposite sides of the carburetors single venturi, this to offer true quadrant tuning of all aspects of fuel delivery in the designs single passage opening. The carburetor main body design may incorporate, a throttle plate(s), a main body assembly, boosters that are associated with a main fuel delivery circuit, idle fuel delivery passages, transfer circuit delivery passages, air venting passages, bowl venting passages and accelerator pump passages. Each can be constructed to offer the design the capability of individually controlling the fuel delivery of both the main, the idle and the transfer circuits to each quadrant of the single venturi design. This is something that previous designs have not offered. By incorporating a modular metering design (metering block 115) in conjunction with the multiple fuel port outlets, this design allows improved control of the delivery of fuel over previous artwork in the single body passage (venturi) designs. A vast improvement over previous artwork and these abilities are a requirement for proper fuel delivery in high horsepower engines to avoid engine damage, maximize power output and improve fuel efficiency.