The All New Holley 625 CFM STREET DEMON CARBURETOR
Updated: Jan 17, 2018
It’s rare to see the release of an all-new carburetor these days. However, that didn’t stop Demon Carburetion now owned by Holley from releasing an all new one, the new 625 Holley Street Demon, with the street/strip buyer in mind. Not only does this carburetor incorporate the latest technology, it will also allow owners, which own stock or only slightly modified hot rods, the chance to have that performance carburetor you’ve always wanted!
The 625 Street Demon is crafted from cast aluminum, giving the carburetor flowing contours and a smooth finish. Made to replace any street four-barrel, the Street Demon design also fits either spread-bore or square-pattern intake manifolds without having to use adapters. But the Street Demon carburetor is more than just good looks and an easy fit. It also features a revolutionary design.
Inside the powerful 1 3/8-inch primary throttle bores, you’ll find triple-stack boost venturii. While two of these boosters are placed across the throttle bores in a conventional fashion, the third booster is integrated into the walls of bores to provide superior fuel emulsification.
The unique booster placement also presents a crisp throttle response as well as favorable fuel economy.
Seamless primary-to-secondary throttle response is taken care of by a torsion spring-controlled air valve that sits at the top of the secondary throttle bores. With the help of its distinct contours, the valve helps ensure optimal throttle response between the primary and secondary throttle bores by providing effective cylinder-to-cylinder fuel distribution no matter what the throttle opening rate is. Torsion spring-adjustable, you can make sure that the air valve is properly positioned with just the turn of a screw.
You’ll also find a goggle valve inside the secondary bores. This valve set at the base of the secondary bores delivers more than twice as much air as the primary bores, giving your car that much desired feel and sound of power.
Integrated into the main body of the 625 Street Demon is the main fuel bowl, which is available in either automotive-spec polymer or aluminum to match the rest of the carburetor. This fuel bowl reduces the transfer of heat to your fuel by up to 20 degrees Fahrenheit, giving you better drivability in hot weather.
The fuel bowl is also highly resistant to leaks since its bowl gasket is positioned above the fuel level it doesn’t include any plugged passages. Simple installation is made possible with a single fuel inlet and tuning can be achieved with two-stage metering rods without removing or disassembling the carburetor. Cold starts are also a non-issue thanks to an electric-assist bi-metal coil choke.
The new 625 Street Demon joins the line of Street Demon carburetors already offered by Demon Carburetion. Available in all aluminum tumble-burnished, tumble-burnished with a polymer fuel bowl, and all aluminum hand polished designs, the 625 Street Demon starts at just $349.99. ( We have them on Sale for $312.95 in the perofrmance section of the web site)
Be sure to check out the new 625 Street Demon as well as all the other carburetor options for a variety of applications from Demon Carburetion on our website!
WICKED POWER! The ALL NEW Street Demon® redefines the street carburetor with clean looks and ease of use! The Street Demon offers enthusiasts a straight forward carburetor designed to deliver a stable idle, amazingly crisp throttle response and smooth performance. Its optimized calibration and dual mounting pattern make it Run–Ready™ for a large variety of engines and vehicles!
Ball burnished shiny aluminum finish
Designed for use on most stock to mildly modified V8s
Developed from the ground up with smooth styling - patented timeless design fits modern as well as traditional themed vehicles (Patent No.: US D648,746 S)
One piece airhorn is easy to clean and maintain
Dual mounting bolt pattern - fits most aftermarket spread/square bore intake manifolds without adapter
Integrated fuel bowl/main body design with gasket above fuel level and no plugged passages to eliminate all potential leak paths
Small 1-3/8” primary throttle bores combined with proven Triple-Stack™ boosters deliver amazingly crisp throttle response and drivability, superior fuel atomization and improved fuel economy
Goggle Valve Secondary (GVS™) throttle plate (Patent # D677755) delivers over twice the air flow of the primary bores for power you can hear and feel
GVS™ makes total air flow 625 CFM while maintaining the crisp throttle response delivered by small primary bores
Secondary air valve control - torsion spring valve control/adjustment permits seamless primary to secondary throttle response regardless of the throttle opening rate (unique contoured profile developed for better cylinder to cylinder fuel distribution)
2 Stage metering rods control easily accessible without carburetor disassembly or removal
Single fuel inlet for simple installation
Integrated 700R4/200R4 transmission kickdown cable mounting location as well as Ford A/T kickdown for proper shifts
Patent pending mechanical design
625 CFM specific calibration kit available for tuning and altitude adjustments
Available TPS kit allows use with 4L60 and 4L80 transmissions
You will find it under Holley part number #1900