Designed with high-horsepower engines in mind, the VRS-4150 950 CFM appeals to racers, engine builders, and carb tuners, as well as hot street enthusiasts seeking to improve performance. The one-piece, cast-aluminum, 3.75”-tall body reaches the 950 CFM rating using 1.562” diameter venturis. Large banjo-style annular boosters provide superior air/fuel mixing. Dual 50cc accelerator pump circuits launch big engines without hesitation. Dual power valves with built-in protection circuits on the primaries and secondaries support optimized jetting to balance the air-fuel ratio.
The VRS includes fully adjustable intermediate fuel circuits and four-circuit billet metering blocks utilizing industry-standard-sized screw-in emulsion bleeds and jets. The intermediate fuel circuit provides extra fuel just after the blade passes the transfer slot for an incredible throttle response. The advanced idle circuit has interchangeable idle-discharge jets with mixture screws in all four corners for a smooth, clean idle when using big, low-vacuum camshafts. For greater fuel-ratio control at high RPM, the high-speed/main fuel circuit is split into two bleed paths – one each for the lower and upper sections. Finally, air bleeds on top of the carburetor provide a quick way to fine-tune each fuel circuit.
Like all VRS-4150s, the 950 fits all 4150 and 4500-style manifolds. It includes a universal street throttle arm with popular transmission kick-down takeoff points, built-in provisions for a standard GM three-wire TPS mount, multiple vacuum ports, and a transmission modulator.
The 20% larger float bowls are designed to control the fuel under harsh conditions. A sculpted baffle directs fuel to the sides of the bowl to minimize bubbles, while perimeter baffles minimize slosh. Meanwhile, bottom corner cuts on the Nitrophyl floats ensure they remain on top, preventing fuel flow shutoff during hard cornering. Jet extenders in the rear bowl keep the jets covered in fuel under hard launches.