- Fuel, Carbs & Intakes
- Carburetors
- Holley Ultra XP Aluminum Carburetors
How to Make the Best, Better!
The Holley HP series carburetors have been the standard in racing carburetors for nearly two decades! So how do you make them better? You make the new Holley Ultra XP Aluminum Carburetors 38% lighter, increase the fuel capacity by 20% and add 30 other new features! They're available in 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. These carburetors are available in 600, 650, 750, 850, and True 950-CFM sizes!
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6061-T6 Billet Aluminum Metering Blocks
- Improved durability, true gasket sealing (sealing surface integrity), bright dipped anodized for good looks and corrosion protection
- Fully adjustable (emulsion bleeds, power valve channel restrictors & idle feed restrictors). Power valve channel restrictors now machined lower in metering block for improved fuel delivery to power valve circuit
- Accelerator pump channel now internally drilled eliminating need for external plug
- Excess material removed for improved fuel capacity
- Integrated pry-point assists in disassembly from fuel bowl and mainbody preventing damage to gaskets and gasket surfaces
- New snap in place bowl vent whistle makes removal and/or replacement easier
6061-T6 Billet Aluminum Base Plate - Improved durability, true gasket sealing, bright dipped anodized for good looks and corrosion protection
- Elongated (dual pattern) mounting holes allow fitment on intakes with square flange (Holley 4150 style) or large flange (Holley Dominator style)
- Dedicated race-only throttle lever with all unnecessary street attachment points & tangs removed
- 950 CFM throttle shaft comes slabbed and undercut for improved airflow
- Stainless steel adjustable secondary link. Provides choice of 1:1 or progressive secondary throttle actuation for ultimate control of secondary opening rate
- 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 throttle stop
- Throttle body and new secondary pump cam lever designed to provide positive throttle stop on secondary side. Delivers safe & reliable 90° opening and return of throttle plates while ensuring maximum airflow
- Baseplate designed with a boss that can be consumer machined for vacuum source
All New Fuel Bowl Design - Completely redesigned from the ground up for racing
- 20% more fuel capacity vs. a traditional v-bowl eliminates fuel starvation and provides consistent air/fuel ratios
- Internal baffling to help control fuel slosh and minimize float level fluctuations in hard launching or cornering situations
- Fuel shelf below the needle and seat to greatly minimize fuel aeration and promote more consistent metering
- Fuel trough designed into floor of bowl to route fuel flow directly to the jets and assist in keeping jets covered by fuel
- Clear Pyrex sight windows on both sides of bowls for easy and safe fuel level adjustments
- (A) Built in drain plug in front center of bowl provides easy access to empty contents of bowl
- (B) Contoured entry provides smooth fuel flow directly to needle & seat
- -08AN (O-ringed) inlet threads offer a large variety of plumbing options (come standard with -08AN O-ring to -06AN male adapter and -08AN plug). Can be plumbed from either side
- Material added in key areas (needle & seat area, fuel inlet, sight window area) for added strength in the demanding race environment
- Note: New lengthened fuel line required due to increased length of bowls
Updated Main Body Design - Air bleeds moved outward to allow a smoother transition of airflow from the top of the carburetor into the venturi
- 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.
- All unnecessary mounting bosses removed for a smoother, cleaner appearance
- Contoured hex head squirter screws for streamlined airflow
- Cast in Holley XP logo for easy identification by race sanctioning bodies
Features: - 100% Holley - Made in the U.S.A.
- 97% aluminum construction
- 38% weight savings
- 20% more fuel bowl capacity
- 10 new fuel bowl features
- 10 new base plate features
- 6 new metering block features
- 5 new main-body features
- 1 new carburetor...Ultra XP
650 CFM
750 CFM
850 CFM
950 CFM
What Are Holley Ultra XP Aluminum Carburetors Common Pros and Cons?
When comparing Holley aluminum carburetor vs zinc options, aluminum designs are usually lighter in weight, with this carburetor at almost 40% lighter than previous designs. The fuel capacity is also 20% larger, reducing the chances of the fuel bowls draining and a reduction in performance. In addition, many improvements have been made over previous models.
Which Holley Ultra XP Aluminum Carburetors Are Best?
When choosing a Holley Ultra XP aluminum carburetor, the first step is confirming the correct CFM size. This is based on the engine cubic inch size and the maximum rpm / redline. From the remaining options, choose the desired finish. When learning how to clean aluminum carburetor after purchasing, use an aluminum-safe cleaner as well as a brush that will not scratch the surface.
How Much Do Holley Ultra XP Aluminum Carburetors Cost?
The price for Holley Ultra XP aluminum carburetors starts at around $1,000 and goes up to the $1,200 range, depending on the size and options.