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Overview
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!
Features:
- 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.
- 30cc primary & 50cc secondary accelerator pumps provide the perfect amount of fuel from idle to full throttle
- 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
- 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!
Specs
| Barrels | 4 |
|---|---|
| Billet Color | Hard Core Gray with Black |
| Booster | Down Leg |
| Brand | Holley |
| CFM | 650 |
| Choke | None |
| Emission Code | 3 |
| Finish | Hard Core Gray |
| Fuel | E-85 |
| Fuel Inlet | Dual |
| High Speed Air Bleed | 28 |
| Idle Air Bleed Size | 70 |
| Material | Aluminum |
| Model | 4150 |
| Primary Main Jet | 76 |
| Primary Power Valve | 5.5 |
| Primary Pump Nozzle Size | 42 |
| Product Type | Ultra XP Carburetor |
| Secondaries | Mechanical |
| Secondary Main Jet | 86 |
| Secondary Pump Nozzle Size | 42 |
| Supercharged Application | No |
| Throttle Bore | 1.688 inch |
| Venturii Size | 1.250 inch |
| Part Number | 0-80842HBX |
Service Parts
![Fuel Bowl Gasket]()
For Model 2300™, Model 4150™, Model 4160™ and Model 4500™ Two Circuit Carburetors$10.31Qty:![Metering Block Gasket]()
For Models 2300™, Model 4150™ Model 4160™ and Model 4500™ without Intermediate Circuit$10.31Qty:![E85 Checker - FOR E85 FUEL ONLY]()
![Carburetor Standard Main Jet]()
![Inlet Needle - Viton]()
Inlet Needle Viton® Tip Adjustable 0.120" Seat Size (Viton® is a registered trademark of DuPont Performance Elastomers)$26.99Qty:![Carburetor Standard Main Jet]()
![Carburetor Standard Main Jet]()
![Fuel Inlet Fitting]()
Short -8AN male fuel inlet fitting (black) with -8AN o-ring threads for Ultra XP fuel bowls.$11.90Qty:![Fast Kit Carburetor Rebuild Kit 4150 Ultra XP Carburetors]()
Holley Fast Kit for 4150 Ultra XP Carburetors$58.40Qty:![Fuel Inlet Fitting]()
Short -8AN male fuel inlet fitting (red) with -8AN o-ring threads for 4150 Ultra XP fuel bowls.$11.90Qty:
Emissions
This part is legal for use on Uncontrolled (Non-Emissions Controlled) Vehicles or Racing Vehicles.
The following vehicles are considered Uncontrolled (Non-Emissions Controlled) Vehicles:
- 1965 and older U.S. manufactured California Certified vehicles
- 1967 and older U.S. manufactured Federally Certified vehicles
- 1967 and older Foreign manufactured vehicle
Racing Vehicles are vehicles that are used exclusively for racing or other forms of competition that are not registered and that may never be used on the street.
*Free Shipping & Handling only offered to the contiguous US on orders over $100.
Some parts are not legal for use in California or other states with similar regulations.