Description

Xtreme Performance – Holley Ultra XP Circle Track Carburetors! Ultra XP carbs are up to 38% lighter than our traditional race carbs, have fuel capacity that is 20% greater and 30 other new features! They’re available in our Hard Core Gray hard coat anodized finish with Black billet for improved corrosion protection & also available in natural tumble-polished aluminum with Black metering blocks and base plate. The Aluminum Ultra XP Circle Track carbs are available in 650 & 750 CFM’s. Holley Ultra XP carburetors are Specifically Calibrated for Circle Track & offer new features such as anti-siphon valve in the main body; high capacity fuel bowls which feature 20% more fuel capacity to eliminate starvation, integrated fuel shelf to minimize fuel aeration and internal baffling to control fuel slosh. Other features include all aluminum construction, fully tunable billet metering blocks, billet base plate, wedge floats, adjustable secondary linkage and knurled (hand adjustable) curb idle screws. Holley Ultra XP carburetors are the ultimate in square bore race carburetors!

Holley has been the undisputed leader in fuel systems for over 100 years. Holley carburetors powered every NASCAR Cup team and nearly every NHRA Pro-Stock champion for four decades. Now, Holley EFI products power these cars and are dominating the performance world. Holley products for GM’s popular LS engine are dominating the LS scene as well. Holley’s products also include performance fuel pumps, intake manifolds and engine dress-up products for street performance, race and marine applications. As a single solution or partnered with products from other Holley companies we can give you the edge you need over the competition!

This carburetor was designed with a dual mounting pattern, so that it can be installed on a manifold machined for a 4150 or 4500 series carburetor.

Shiny with black anodized billet aluminum metering blocks and base plate

Calibrated specifically for use on circle track

Has a set screw in the base plate for wide open throttle stop adjustment

PTFE coated throttle shafts rides in oil impregnanted bronze bushings for smooth throttle actuation

Anti-siphon valve in main body to reduce pump pullover

Contoured venturri inlet offers balanced airflow for increased horsepower

Air bleeds moved outward to allow a smoother transition of airflow from the top of the carburetor into the venturii

Metering blocks feature improved durability, true gasket sealing and fully adjustable (emulsion bleeds, power valve channel restrictors & idle feed restrictors)

Integrated idle bypass valve eliminates the need for holes in throttle plates and allows for proper adjustment of idle while maintaining correct throttle plate to transfer slot relationship. Helps maintain good idle control when using radical camshafts.

Dual 30cc accelerator pumps provide the perfect amount of fuel from idle to full throttle

Fuel bowls provide 20% more fuel capacity while controlling slosh with internal baffling

Clear sight windows on both sides of bowls for easy and safe fuel level adjustments

Built in drain plug in front center of bowl provides easy access to empty contents of bowl

-8 (o-ringed) inlet threads offer a large variety of plumbing options and can be plumbed from either side

4 corner idle allows you to precisely control your idle system

Internal pump passage in metering block equipped with a tunable bleed off for further tuning of accelerator pump

Knurled (hand adjustable) primary and secondary curb idle screws allow for easy idle adjustment without the use of tools

Primary throttle shaft capped to prevent entry of debris & contaminates

Factory machined accessory mounting hole for easy addition of adjustable primary throttle stop. New secondary pump cam lever designed to provide positive throttle stop on secondary side

Set up with 1:1 throttle actuation

Baseplate designed with a boss that can be consumer machined for vacuum source

Includes wedge floats

100% wet-flow tested by Holley technicians to assure it arrives ready to run!

Product :

Carburetor

Ultra XP

Model 4150

4-Barrel

750 CFM

Square Bore

No Choke

Mechanical Secondary

Dual Inlet

Aluminum

Black Anodized / Tumble Polished

Sold Individually

For over a century Holley has driven the cutting edge of fuel-system design. That work continues today through Holley’s market-leading EFI products as well as through Holley’s family of best-in-industry brands. Top brands like MSD, Flowmaster, Hurst, Accel, and many more make up the industry’s leading offering of enthusiast-driven products to deliver robust, complete performance solutions for builders, racers, and drivers. From propelling the LS-, Coyote-, and Gen 3 Hemi-swap trends, to continuously innovating late-model and vintage vehicle performance, Holley’s commitment to its customers and their cars is at the core of everything we do.