0-80845HBX Ultra XP E85 Aluminum Carburetor 4-Barrel

Name: 0-80845HBX Ultra XP E85 Aluminum Carburetor 4-Barrel
Brand: HOLLEY
SKU: 510-0-80845HBX
Price: 1348.95 USD
Availability: InStock

^$1,348⁹⁵$1499.95You Save$151.00

Ships on 11/03/2026

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950 cfm

Ultra XP E85 Aluminum Carburetor

4-Barrel

950 cfm

Hard Core Gray Finish

Holley 0-80845HBX Features:

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!

Aluminum Construction (saves 4.5 lbs - 38% weight savings)
Hard Core Gray with black anodized billet aluminum metering block and booster inserts
Designed for use on Drag race, circle track, or any high horsepower engines
E85 specific calibration
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.
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
.130" stainless needle & seats to control the demand of E-85
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 & contaminates
Throttle shaft is slabbed and undercut for improved airflow
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
Stainless steel throttle plates
Includes notched float and jet extensions
100% wet-flow tested by Holley technicians to assure it arrives ready to run!

Emissions Note:

This part is only legal for sale and use on Uncontrolled (Non-Emissions Controlled) Vehicles or on vehicles used solely for the purposes of closed competition racing.

CLICK THIS LINK FOR IMPORTANT CARB & EPA EMISSIONS INFORMATION ABOUT THIS PART

Holley Ultra XP E85 Aluminum Carburetors incorporate 30 new features! Specifically designed and calibrated for E85 fuel in drag race or circle track applications, these carbs are anodized Hard Core Gray with black accents.

Overview

Compatible with E85 fuel
Available cfm: 500, 600, 650, 750, 850, 950
38% lighter because 97% aluminum construction

Anodized Hard Core Gray with black billet accents
Premium finish protects against ethanol's corrosive properties
20% more fuel capacity compared to standard V-bowl
and 100% Holley

Updated Main Body
Cast Holley logo for easy identification by race officials
Contoured hex head squirter screws for streamlined airflow
All unnecessary mounting bosses removed for a cleaner appearance
Air bleeds moved outward for smoother airflow transition from the top of the carburetor into the venturii
Idle bypass valve eliminates the need for throttle plate holes, allows proper idle adjustment, and maintains idle control with radical camshafts

All-New Fuel Bowl Design
Completely redesigned for racing
Longer fuel line required due to increased bowl length
Built-in drain plug (front center) for easy access to empty bowl
Contoured entry flows fuel smoothly and directly to needle & seat
Clear Pyrex sight windows (both sides) for safe, simple fuel level adjustment
Greater fuel capacity prevents fuel starvation and provides consistent air/fuel ratio
Fuel trough in the bowl "floor" routes fuel directly to the jets and helps keep jets submerged
Fuel shelf below needle & seat minimizes fuel aeration and promotes more consistent metering
Material added to needle & seat area, fuel inlet, and sight window area to enhance strength for racing
Internal baffling controls fuel slosh and reduces float level fluctuation during hard launches and cornering
-8AN O-ring inlet threads offer many plumbing options from either side (standard with -8AN O-ring to -6AN male adapter and -8AN plug)

6061-T6 Billet Aluminum Baseplate
Boss can be machined for vacuum source
Primary throttle shaft capped to keep out debris/contaminants
True gasket sealing, superior corrosion protection, and improved durability
Factory-machined accessory mounting hole for easy addition of adjustable throttle stop
Knurled primary and secondary curb idle screws allow idle adjustment by hand without tools
Dedicated race-only throttle lever (all unnecessary street attachment points & tangs removed)
Elongated, dual pattern mounting holes accommodate intakes with square flange (Holley 4150) or large flange (Holley Dominator)
Stainless steel secondary link offers choice of 1:1 or progressive secondary throttle actuation for ultimate control of secondary opening rate
Throttle body & secondary pump cam lever provide positive throttle stop on secondary side for a reliable 90° opening/return of throttle plates

6061-T6 Billet Aluminum Metering Blocks
Excess material removed for greater fuel capacity
Snap-in-place bowl vent whistle simplifies removal/replacement
True gasket sealing, superior corrosion protection, and improved durability
Accelerator pump channel internally drilled to eliminate need for external plug
Pry-point assists in disassembly from fuel bowl and main body to prevent gasket damage
Fully adjustable (emulsion bleeds, power valve channel restrictors, and idle feed restrictors)
Power valve channel restrictors machined lower in metering block for better fuel delivery to power valve circuit

Carburetor Technical Specifications Guide, Click Here