Ultra XP 2-Barrel Carburetor500 CFMHard Core Gray w/Black Holley 0-4412HBX Features:The original Holley 0-4412 has powered thousands of racers to the winners' circle! How do you make it better? Add the proven design elements of the popular Ultra series for more tunability, more durability, more weight savings and more features! The Ultra XP 2bbl carburetors feature all aluminum construction for nearly 50 weight savings over their zinc counterparts, contoured venturii inlet for unobstructed airflow, screw in air bleeds for easy fine tuning, black anodized fully adjustable billet aluminum metering block and baseplate, high capacity fuel bowl which features 20 more fuel capacity to eliminate starvation, integrated fuel shelf to minimize fuel aeration and internal baffling to.