Xtreme Performance - Holley 4150 Aluminum Ultra XP 850 CFM Carburetor (Hard Black)

Introducing the Holley Ultra XP™ carburetors, designed for those who crave performance! These Ultra XP carbs are a game changer, being up to 38% lighter than traditional race carbs, and they boast a 20% larger fuel capacity along with a host of 30 innovative features! Available in a striking Hard Core Gray™ hard coat anodized finish paired with Black™ billet components, these carburetors offer enhanced corrosion protection. You can also choose from a natural tumble-polished aluminum option with your pick of Black™ or Red™ metering blocks and base plate. The Aluminum Ultra XP comes in various sizes, including 600, 650, 750, 850, and True 950-CFM.

What sets the Holley Ultra XP carburetors apart? They come equipped with a built-in idle bypass valve, allowing you to make idle adjustments while keeping the throttle plate to transfer slot relationship just right. With high-capacity fuel bowls that provide 20% more fuel capacity, you can say goodbye to fuel starvation. The integrated fuel shelf minimizes aeration, and internal baffling helps control fuel slosh. Other standout features include all-aluminum construction, fully tunable billet metering blocks, a billet base plate, adjustable secondary linkage, and knurled (hand adjustable) curb idle screws. Holley Ultra XP carburetors are truly the pinnacle of square bore race carburetors!

• Instructions for Part# 0-80804HBX
• Carburetor Numerical Listing for Part #0-80804HBX

• Aluminum construction saves 4.5 lbs – that’s a 38% weight reduction!
• Hard Core Gray finish with black anodized billet aluminum metering block and booster inserts
• Perfect for drag racing, circle track, or any high horsepower engine
• Contoured venturi inlet ensures balanced airflow for a boost in horsepower
• Air bleeds are strategically placed for smoother airflow transitions
• Durable metering blocks with true gasket sealing and fully adjustable features (emulsion bleeds, power valve channel restrictors & idle feed restrictors)
• Integrated idle bypass valve eliminates the need for throttle plate holes, allowing for accurate idle adjustments
• Dual 30cc accelerator pumps deliver the right amount of fuel from idle to full throttle
• Fuel bowls have 20% more capacity and control slosh with internal baffling
• Clear sight windows on both sides of the bowls for easy fuel level checks
• Convenient front center drain plug for easy bowl emptying
• 8AN (o-ringed) inlet threads provide versatile plumbing options
• Four corner idle system for precise idle control
• Mechanical secondaries for smooth launches off the line
• Elongated mounting holes accommodate both square flange (Holley 4150™ style) and large flange (Holley Dominator® style) intakes
• Knurled primary and secondary curb idle screws allow for tool-free adjustments
• Primary throttle shaft is capped to keep out debris and contaminants
• Factory machined accessory mounting hole for easy addition of an adjustable primary throttle stop
• New secondary pump cam lever designed for a positive throttle stop on the secondary side
• Stainless steel adjustable secondary link for ultimate control over the secondary opening rate
• Baseplate features a boss that can be machined for vacuum source
• Includes notched float and jet extensions
• 100% wet-flow tested by Holley technicians to ensure it’s ready to run right out of the box!

• Barrels: 4
• Billet Color: Hard Core Gray with Black
• Booster: Down Leg
• CFM: 850
• Choke: None
• Circuit: 2
• Emission Code: 3
• Finish: Hard Core Gray
• Fuel: Gasoline
• Fuel Inlet: Dual
• Material: Aluminum
• Model: 4150
• Primary Main Jet: 84
• Primary Power Valve: 4.5
• Primary Pump Nozzle Size: 32
• Product Type: Ultra XP Carburetor
• Secondaries: Mechanical
• Secondary Main Jet: 84
• Secondary Pump Nozzle Size: 32
• Supercharged Application: No
• Throttle Bore: 1.750 inch
• Venturi Size: 1.563 inch
• Warranty: Limited 90 Day

• 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 your intake manifold is of the spreadbore style, you will need an adapter for installation, similar to the Mr. Gasket #1932.