Overview

Holley Aluminum Ultra XP 2-Barrel Carburetors

Holley improved the carburetor that powered thousands of racers into the winner's circle—Holley Ultra XP 2-barrel carburetors. They used the original 0-4412 and added the proven design elements of their Ultra Series delivering the XPs with more tunability, more durability, more weight savings, and more features! They are approved for use in NASCAR Mid-West/West Coast Late Model Divisions and utilize the same venturii and throttle bore dimensions of the classic 2-barrel carburetor. Holley Ultra XP carburetors are available in different finishes, and will outperform any production 2-barrel available.

Features include:

* All-aluminum construction for nearly 50 percent weight savings over zinc versions
* Tumble polished aluminum with Black billet aluminum metering block and base plate
* No choke tower for unobstructed airflow
* Air bleeds moved outward to allow a smoother transition of airflow
* Air cleaner flange centered over venturii for improved airflow and performance, 5/16 in.-18 bent air cleaner stud included
* Down-leg boosters for improved fuel signal
* Contoured hex head squirter screw for streamlined airflow
* Internal pump passage on metering block equipped with tunable bleed off
* Same original 1 3/8 in. venturii and 1 11/16 in. throttle bore size and throttle plate/shaft size
* Fuel bowl provides 20 percent more fuel capacity while controlling slosh with internal baffling
* Clear sight windows on both sides of bowl for easy and safe fuel level adjustments
* Fuel trough designed into floor of bowl to route fuel flow directly to the jets and assists in keeping jets covered by fuel
* Built-in drain plug provides easy access to empty contents of bowl
* -8 (O-ring) inlet threads offer a large variety of plumbing options (come with an extended -8 O-ring to -8AN male adapter and -8 plug). Can be plumbed from either side
* Throttle shaft rides in oil impregnated sintered bronze bushings for smooth throttle actuation
* Throttle shaft capped to prevent entry of debris and contaminates
* 30cc pump with metal lever. Anti-siphon valve in main body to reduce pump pull-over
* Dedicated race-only throttle lever with all unnecessary street attachment points and tangs removed
* Knurled (hand adjustable) curb idle screw allows for easy idle adjustment without the use of tools
* Set screw for wide open throttle stop adjustment
* Wedge float provides fuel control while cornering
* 100 percent wet-flow tested by Holley technicians to assure it arrives ready to run!

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