Xtreme Performance - Holley Ultra XP™ Carburetors

Meet the Holley Ultra XP™ carburetors, designed for those who crave performance! These carburetors are an impressive 38% lighter than our traditional race models, and they come with a 20% larger fuel capacity along with a host of 30 innovative features. You can choose from the striking Hard Core Gray™ hard coat anodized finish paired with Black™ billet for enhanced corrosion resistance, or opt for the natural tumble-polished aluminum with your pick of Black™ or Red™ metering blocks and base plate. The Aluminum Ultra XP is available in sizes of 600, 650, 750, 850, and a true 950-CFM. These carburetors are packed with new features, including an integrated idle bypass valve that allows for precise idle adjustments while keeping the throttle plate and transfer slot relationship just right. The high-capacity fuel bowls, which boast 20% more fuel capacity, help eliminate fuel starvation, while the integrated fuel shelf minimizes aeration and internal baffling controls fuel slosh. With all-aluminum construction, fully tunable billet metering blocks, a billet base plate, adjustable secondary linkage, and knurled curb idle screws that you can adjust by hand, Holley Ultra XP carburetors truly stand out as the ultimate choice for square bore race applications!

Important Downloads:

• Instructions for Part# 0-80845HBX
• Carburetor Numerical Listing for Part #0-80845HBX

Features:

• Lightweight aluminum construction saves 4.5 lbs - that's a 38% weight reduction!
• Stylish Hard Core Gray finish with black anodized billet aluminum metering block and booster inserts
• Perfectly designed for drag racing, circle track, or any high horsepower engine
• Specifically calibrated for E85 fuel
• Contoured venturi inlet ensures balanced airflow for increased horsepower
• Air bleeds positioned outward for a smoother airflow transition
• Durable metering blocks with true gasket sealing and fully adjustable features
• Integrated idle bypass valve allows for proper idle adjustments without throttle plate holes, maintaining excellent idle control, even with radical camshafts.
• Fuel bowls with 20% more capacity and internal baffling to manage slosh
• Clear sight windows on both sides of the bowls for safe and easy fuel level checks
• Convenient drain plug located at the front center of the bowl
• 8AN (o-ringed) inlet threads for versatile plumbing options
• .130" stainless needle and seats to effectively manage E-85 demands
• Four corner idle system for precise idle control
• Mechanical secondaries for perfect launches every time
• Elongated mounting holes for compatibility with square flange (Holley 4150™ style) or large flange (Holley Dominator® style) intakes
• Knurled primary and secondary curb idle screws for easy adjustments without tools
• Primary throttle shaft is capped to keep out debris and contaminants
• Throttle shaft design enhances airflow
• Factory machined accessory mounting hole for easy addition of adjustable primary throttle stop
• New secondary pump cam lever ensures positive throttle stop on the secondary side
• Stainless steel adjustable secondary link allows for 1:1 or progressive throttle actuation
• Baseplate designed with a boss for consumer machining for vacuum source
• Stainless steel throttle plates for durability
• Includes notched float and jet extensions
• Each unit is 100% wet-flow tested by Holley technicians to ensure it’s ready to run!

Specifications:

• Barrels: 4
• Billet Color: Hard Core Gray with Black
• Booster: Down Leg
• CFM: 950
• Choke: None
• Emission Code: 3
• Finish: Hard Core Gray
• Fuel: E-85
• Fuel Inlet: Dual
• High Speed Air Bleed: 24
• Idle Air Bleed Size: 67
• Material: Aluminum
• Model: 4150
• Primary Main Jet: 96
• Primary Power Valve: 5.5
• Primary Pump Nozzle Size: 42
• Product Type: Ultra XP Carburetor
• Secondaries: Mechanical
• Secondary Main Jet: 106
• Secondary Pump Nozzle Size: 50
• Supercharged Application: No
• Throttle Bore: 1.750 inch
• Venturi Size: 1.600 inch
• Warranty: Limited 90 Day

Notes:

• This carburetor features a square bore flange bolt pattern, making it compatible with Holley, Edelbrock, Carter AFB, and Autolite style carburetors that have a 5 3/16" x 5 5/8" bolt pattern. If you're working with a spreadbore style intake manifold, an adapter will be necessary for installation, similar to the Mr. Gasket #1932.