Xtreme Performance - Holley 4150 ALUM Ultra XP 950 CFM (Hard Black)

Meet the Holley Ultra XP™ carburetors, designed for those who crave performance and efficiency! These Ultra XP carbs are remarkably up to 38% lighter than our standard race carbs, while boasting a fuel capacity that's 20% greater. With 30 innovative features, you’ll be impressed by what they bring to the table!

Available in a striking Hard Core Gray™ hard coat anodized finish paired with a Black™ billet for enhanced corrosion protection, these carburetors also come in a natural tumble-polished aluminum option. You can choose between stylish Black™ or Red™ metering blocks and base plates. The Aluminum Ultra XP is offered in sizes of 600, 650, 750, 850, and a true 950 CFM.

What sets the Holley Ultra XP carburetors apart? For starters, they feature an integrated idle bypass valve that allows you to adjust the idle without compromising the throttle plate to transfer slot relationship. Plus, the high-capacity fuel bowls provide 20% more fuel capacity to prevent starvation, while the integrated fuel shelf minimizes aeration, and internal baffling keeps fuel slosh in check.

With an all-aluminum construction, fully tunable billet metering blocks, and an adjustable secondary linkage, these carburetors are not just functional; they’re also user-friendly with knurled (hand adjustable) curb idle screws. The Holley Ultra XP carburetors are truly the pinnacle of square bore race carburetors!

• Instructions for Part# 0-80805HBX
• Carburetor Numerical Listing for Part #0-80805HBX

• Lightweight aluminum construction (saves 4.5 lbs - 38% weight savings)
• Hard Core Gray with black anodized billet aluminum metering block and booster inserts
• Perfect for Drag racing, circle track, or any high horsepower engines
• Contoured venturi inlet for balanced airflow, boosting horsepower
• Air bleeds strategically placed for smoother airflow transition
• Durable metering blocks with true gasket sealing and full adjustability
• Integrated idle bypass valve for precise idle adjustments without throttle plate holes
• Dual 30cc accelerator pumps for optimal fuel delivery from idle to full throttle
• Fuel bowls with 20% increased capacity and internal baffling to manage slosh
• Clear sight windows for easy and safe fuel level monitoring
• Convenient drain plug for quick access to empty fuel bowls
• 8AN (o-ringed) inlet threads for versatile plumbing options
• 4 corner idle for precise control over your idle system
• Mechanical secondaries for powerful launches off the line
• Elongated (dual pattern) mounting holes for easy fitment on various intakes
• Knurled (hand adjustable) curb idle screws for effortless adjustments
• Primary throttle shaft capped to keep out debris and contaminants
• Throttle shaft design optimized for improved airflow
• Factory machined accessory mounting hole for easy throttle stop addition
• Stainless steel adjustable secondary link for optimal control of secondary opening rate
• Baseplate includes a boss for potential vacuum source machining
• Comes with notched float and jet extensions
• 100% wet-flow tested by Holley technicians to ensure it’s ready to rock!

• Barrels: 4
• Billet Color: Hard Core Gray with Black
• Booster: Down Leg
• CFM: 950
• Choke: None
• Circuit: 2
• Emission Code: 3
• Finish: Hard Core Gray
• Fuel: Gasoline
• Fuel Inlet: Dual
• Material: Aluminum
• Model: 4150
• Primary Main Jet: 92
• Primary Power Valve: 4.5
• Primary Pump Nozzle Size: 32
• Product Type: Ultra XP Carburetor
• Secondaries: Mechanical
• Secondary Main Jet: 92
• Secondary Power Valve: 4.5
• Secondary Pump Nozzle Size: 32
• Supercharged Application: No
• Throttle Bore: 1.750 inches
• Venturi Size: 1.600 inches
• Warranty: Limited 90 Day

• This model 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 using a spreadbore style intake manifold, an adapter will be necessary for installation, similar to the Mr. Gasket #1932.