Written by Moore Good Ink
Bowling Green KY: The introduction of an all-new carburetor, especially in this millennium, has become increasingly rare. But Demon Carburetion has done just that. Named the 625 Street Demon, it is engineered for hot rods with stock to mildly modified engines.
In appearance, its cast aluminum construction exhibits smooth and flowing contours and in operation it accommodates either square- or spread-bore-pattern intake manifolds without adapters. It’s an easy replacement for any street four-barrel.
Developed from clean-sheet beginnings, the Street Demon features two potent 1-3/8in primary throttle bores, which contain triple-stack boost venturii. Two of the boosters are suspended across the bores in the conventional way; the third is neatly integrated into the throttle bore walls. Their purpose is calculated to produce superior fuel emulsification, to present crisp throttle response and drivability, and to provide pleasing fuel economy.
At the top of secondary bores a torsion spring-controlled air valve resides. Its function is to ensure seamless primary-to-secondary throttle response, regardless of the throttle opening rate. Its two distinctive, sloping contours are engineered for efficient cylinder-to-cylinder fuel distribution. Torsion spring adjustment of the valve is controlled by a screw on the end of its shaft axis.
The Street Demon’s fuel bowl, which is integrated with the main body, is available in either aluminum or an exclusive automotive-spec polymer. The polymer bowl demonstrates impressive hot-weather drivability and faster hot restarts by reducing heat transfer to the fuel by as much as 20 degrees Fahrenheit. To eliminate all potential leaks the bowl is devoid of plugged passages and the bowl gasket is placed above the fuel level.
A single fuel inlet ensures simple installation and two-stage metering rods accommodate most tuning requirements, without carburetor disassembly or removal. For cold starting, a proven electric-assist bimetal coil choke is provided.
Street Demons are available in three forms: all aluminum tumble-burnished, tumble-burnished with polymer fuel bowl, and all aluminum hand polished. Prices are $349.99, $379.99 and $449.99 respectively.