Edelbrock VRS-4150 Race & Performance Carburetors are street friendly but race ready. The one-piece, cast aluminum body fits all 4150 and 4500 carb flange manifolds without requiring an adapter plate. Street throttle arm, Moly-coated throttle shafts and built-in provisions for standard GM three-wire TPS mount. Multiple vacuum hook-ups keep this carburetor usable on the street but still ready for the track with larger capacity fuel bowls and four circuit billet metering blocks with screw-in emulsion bleeds. 20% larger capacity fuel bowls feature internal ribs to control fuel slosh, and a sculpted baffle directs incoming fuel to the sides to minimize bubbles. The floats have corner cuts to avoid shutting off the fuel flow during hard cornering, and jet extender notches and jet extenders in the rear to keep the jets covered in fuel under hard acceleration. VRS carburetors allow users to externally adjust idle bypass air as the adjustment screws are accessible without removing the air cleaner/scoop. The advanced idle circuit features interchangeable idle discharge jets in all four corners allows for a smooth, clean idle with the use of big, low-vacuum camshafts. VRS includes fully adjustable intermediate fuel circuits normally found only in high end racing carbs, which help to provide incredible throttle response. For greater control at high RPM, the high speed/main fuel circuit is split into two bleed circuits – one each for the lower and upper sections. The power valves are located on both primaries and secondaries that support optimized jetting. The power valve will add fuel as necessary while the power valve protection circuit prevents diaphragm damage from backfires.