Xtreme Performance - Holley Ultra XP™ Carburetors! Get ready to experience the next level with the Holley Ultra XP carburetor, designed to be up to 38% lighter than traditional race carbs. With a fuel capacity that’s 20% greater, plus 30 innovative features, this carb is built for serious performance enthusiasts!

Available in a striking Hard Core Gray™ hard coat anodized finish with Black™ billet for top-notch corrosion protection, the Aluminum Ultra XP also comes in a natural tumble-polished aluminum option. You can choose between Black™ or Red™ metering blocks and base plates to match your style. This model is offered in various sizes, including 600, 650, 750, 850, and True 950-CFM, catering to your specific needs.

The Holley Ultra XP carburetors boast a range of new features, such as an integrated idle bypass valve that makes idle adjustments a breeze while keeping the throttle plate to transfer slot relationship just right. With high-capacity fuel bowls that offer 20% more fuel capacity, you won’t have to worry about starvation. An integrated fuel shelf minimizes fuel aeration, and internal baffling controls fuel slosh effectively.

Constructed entirely from aluminum, these carburetors feature fully tunable billet metering blocks and a billet base plate. The adjustable secondary linkage and knurled (hand adjustable) curb idle screws make fine-tuning your setup easy. Holley Ultra XP carburetors are the ultimate choice for square bore race carburetors!

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

• Lightweight aluminum construction (saves 4.5 lbs - 38% weight savings)
• Stylish black anodized billet aluminum metering blocks and base plate
• Perfect for drag racing, circle track, or any high horsepower engine
• Contoured venturi inlet for balanced airflow and increased horsepower
• Air bleeds strategically moved outward for smoother airflow transition
• Durable metering blocks with true gasket sealing and full adjustability (emulsion bleeds, power valve channel restrictors & idle feed restrictors)
• Integrated idle bypass valve eliminates the need for throttle plate holes, ensuring proper idle adjustments
• Dual 30cc accelerator pumps deliver the ideal fuel amount from idle to full throttle
• Fuel bowls with 20% more capacity and internal baffling to control slosh
• Clear sight windows on both sides of bowls for easy fuel level adjustments
• Convenient drain plug at the front center of the bowl for quick emptying
• 8AN (o-ringed) inlet threads provide versatile plumbing options
• 4 corner idle for precise idle system control
• Mechanical secondaries for perfect launches off the line
• Elongated mounting holes accommodate both square flange (Holley 4150™ style) and large flange (Holley Dominator® style) intakes
• Knurled (hand adjustable) primary and secondary curb idle screws for effortless adjustments
• Primary throttle shaft capped to keep out debris and contaminants
• Factory machined accessory mounting hole for easy addition of adjustable primary throttle stop
• New secondary pump cam lever for positive throttle stop on the secondary side
• Stainless steel adjustable secondary link for ultimate control of secondary opening rate
• Baseplate designed with a boss for potential vacuum source machining
• 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: Shiny with Black Billet
• Booster: Down Leg
• CFM: 850
• Choke: None
• Circuit: 2
• Emission Code: 3
• Finish: Shiny
• 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 you’re using a spreadbore style intake manifold, an adapter will be necessary for installation, similar to the Mr. Gasket #1932.