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Holley 0-80804BKX 850CFM Ultra Xp Carburetor

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Holley 0-80804BKX 850CFM Ultra Xp Carburetor
Holley

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#425080804BKX

Holley 0-80804BKX 850CFM Ultra Xp Carburetor

$1,168.95

/each

Factory Shipped

$1,299.95

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Product Summary

4-Barrel Carburetor Barrels, Gasoline Fuel Type, Shiny

    Rebates Available

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    Key Specs

    Carburetor Barrels4-Barrel
    Fuel TypeGasoline
    Choke TypeNo Choke
    CFM Range800-899 CFM
    CFM850 CFM
    See more specs

    Need To Know

    Need help?

    855.313.9176
    View the Help Center

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    Holley 0-80804BKX Details

    Xtreme Performance - Holley Ultra XP™ 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 all-new Hard Core Gray™ hard coat anodized finish with Black™ billet for improved corrosion protection. They're also available in natural tumble-polished aluminum with your choice of Black™ or Red™ metering blocks and base plate. The Aluminum Ultra XP comes in 600, 650, 750, 850, and True 950-CFM. Holley Ultra XP carburetors offer new features such as an integrated idle bypass valve that allows for idle adjustments while maintaining the correct throttle plate to transfer slot relationship, 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, adjustable secondary linkage and knurled (hand adjustable) curb idle screws. Holley Ultra XP carburetors are the ultimate in square bore race carburetors!

    Features:

  • Aluminum Construction (saves 4.5 lbs - 38% weight savings)
  • Shiny with black anodized billet aluminum metering blocks and base plate
  • Designed for use on Drag race, circle track, or any high horsepower engines
  • 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 And 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
  • 8AN (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
  • Mechanical Secondaries for perfect off the line launches
  • Elongated (dual pattern) mounting holes allow fitment on intakes with square flange (Holley 4150™ style) or large flange (Holley Dominator® style)
  • 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 And 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
  • Stainless steel adjustable secondary link. Provides choice of 1:1 or progressivesecondary throttle actuation for ultimate control of secondary opening rate
  • Baseplate designed with a boss that can be consumer machined for vacuum source
  • Includes notched float and jet extensions
  • 100% wet-flow tested by Holley technicians to assure it arrives ready to run!

    • Rebates

    Holley October Promo 10% Off Select Parts Sale

    Holley October Promo 10% Off Select Parts SaleHolleyOctoberPromo10%OffSelectPartsSale

    Holley's October Promo 10% Off Select Parts Sale, running from September 28, 2026, through November 1, 2026. For a limited time, customers can save up to 10% off on select Holley parts, making it the perfect opportunity to upgrade your ride with premium Holley branded parts including Holley, Brawler, Quick Fuel, Leg Wheels, Rev Wheels, Rocket Racing, Flowtech, Edge, Racequip, Apr and Dinan. Purchases must be made between September 28, 2026, through November 1, 2026. This limited-time offer applies to qualifying Holley branded parts purchased during the promotional period. Following the promotion, these parts will revert back to standard pricing.

    CARB Warning

    For use on pre-1966 vehicles only

    Emissions warning: this part only legal for sale or use in California if installed in vehicles model-year 1965 or older; motorcycles model-year 1977 or older; or off-highway recreational vehicles (such as off-road motorcycles and all-terrain vehicles) model-year 1996 and older. ++any other use renders the vehicle tampered and not legal for use on California public highways (any public street or roadway, public dirt road, public park, or publicly maintained right of way open to the use of the public for vehicular travel). Violations subject to $37,500 penalty per violation per vehicle, revocation of registration, loss of use on California public right of ways, and proof of correction for tampering there are similar restrictions and penalties under federal law and the laws of all other states with penalties under federal law of up to approximately $45,268 per tampered vehicle and/or engine.
    CA Prop 65
    CARB warning

    Holley 0-80804BKX Specifications

    KEY SPECS
    MFG. Part #0-80804BKX
    BrandHolley
    Carburetor Barrels4-Barrel
    Fuel TypeGasoline
    Choke TypeNo Choke
    CFM Range800-899 CFM
    CFM850 CFM
    Carburetor Flange TypeDual: Square and Dominator
    FinishShiny
    Material TypeAluminum
    ColorSilver
    Secondary TypeMechanical
    Fuel Inlet TypeDual
    Gasket(s) IncludedYes
    New or RemanufacturedNew
    Throttle Linkage TypeUniversal
    Supercharged ApplicationNo
    GENERAL
    Carburetor Height3.25
    Primary Power Valve4.5 Hg
    Primary Jet Size84
    Secondary Jet Size84
    Primary Outer Air Bleed Sizes Included67
    Primary Inner Air Bleed Sizes Included34
    Secondary Outer Air Bleed Sizes Included67
    Secondary Inner Air Bleed Sizes Included34
    Primary Discharge Nozzle Size0.031
    Secondary Discharge Nozzle Size0.031
    NotesBillet aluminum black anodized metering blocks. -8AN O-ringed inlet threads. Come standard with -8AN o-ring to -6AN male adapter and -8AN plug. Can be plumbed from either side.
    GTIN Code090127713464
    Sold in QuantityEach
    Secondary Power Valve4.5

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