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Description
Holley 0-80813BKX 750 CFM Aluminum Ultra XP Circle Track Carburetor750 CFM 4150 Mechanical Secondaries Shiny Gasoline Part Number: 0 80813BKX Xtreme Performance Holley Ultra XP Circle Track 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 Hard Core Gray hard coat anodized finish with Black billet for improved corrosion protection & also available in natural tumble polished aluminum with Black
750 CFM - 4150 - Mechanical Secondaries - Shiny - GasolinePart Number: 0-80813BKX
Xtreme Performance - Holley Ultra XP™ Circle Track 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 Hard Core Gray™ hard coat anodized finish with Black™ billet for improved corrosion protection & also available in natural tumble-polished aluminum with Black™ metering blocks and base plate. The Aluminum Ultra XP Circle Track carbs are available in 650 & 750 CFM's. Holley Ultra XP carburetors are Specifically Calibrated for Circle Track & offer new features such as anti-siphon valve in the main body; 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, wedge floats, adjustable secondary linkage and knurled (hand adjustable) curb idle screws. Holley Ultra XP carburetors are the ultimate in square bore race carburetors!
Features and Benefits
• Aluminum Construction (saves 4.5 lbs - 38% weight savings)
• Shiny with black anodized billet aluminum metering blocks and base plate
• Calibrated specifically for use on circle track
• Has a set screw in the base plate for wide open throttle stop adjustment
• PTFE coated throttle shafts rides in oil impregnanted bronze bushings for smooth throttle actuation
• Anti-siphon valve in main body to reduce pump pullover
• 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.
• Dual 30cc 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
• -8 (o-ringed) inlet threads offer a large variety of plumbing options and can be plumbed from either side
• 4 corner idle allows you to precisely control your idle system
• Internal pump passage in metering block equipped with a tunable bleed off for further tuning of accelerator pump
• 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
• Set up with 1:1 throttle actuation
• Baseplate designed with a boss that can be consumer machined for vacuum source
• Includes wedge floats
• 100% wet-flow tested by Holley technicians to assure it arrives ready to run!
This carburetor was designed with a dual mounting pattern, so that it can be installed on a manifold machined for a 4150 or 4500 series carburetor.
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- Standard Shipping : 3-10 business days
- If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
- We offer a 30-day return/exchange service after receiving.
- Final sale items are not eligible for returns or exchanges.
- To process your return/exchange, please contact us at [email protected]
- Please click here for more details>>> Return & Exchange Policy
4.7 ★★★★★
Based on 23 reviews
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Product Reviews
★★★★★ 5
I will buy these again.
Size: 12-13, Color: Cable Knit Brown
These are great. They’re warm and comfortable.
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Reviewed in the United States on May 5, 2026
★★★★★ 5
Quality and comfort
Size: 10.5-11.5 Women/9-10 Men, Color: Black
Comfortable and fit well. I got these to replace a very old pair that finally wore out! Warmth is medium (I wear puffer booties for when it's really cold). Quality on these is great!
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Reviewed in the United States on March 9, 2026
★★★★★ 5
Can't go wrong with Acorn for as long as they last!
Size: 12-13 Women/10.5-11.5 Men, Color: Charcoal
Acorn is just a great company all around. I had bought my husband these slippers over 20 years ago. They are still in great shape although the sole has worn in some places. But nothing's coming apart! However, I decided to replace them for him. His foot is 10.5 and they are a little hard to get on right away-of course, after over 20 years of having "worn in" the original pair, anything would feel tight. So I'm not holding this against them. They will relax with use. The only difference is that the original sole was black and these are tan. I think I would prefer the black, but since it's only being worn in the house, no big deal.
My husband has really cold feet and these slippers never fail to warm his feet right up! He said they feel really soft to walk in and like the cushioning. They're not too heavy and fit him great! I have Acorn slippers myself that I've worn every single day in the house and outside to the mailbox too. They last.
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Reviewed in the United States on April 11, 2026
★★★★★ 4
Very warm.
Size: 13.5-14.5 Women/12-13 Men, Color: Navy Blue
Very warm and comfortable. A little difficult to put on with the collared top.
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Reviewed in the United States on January 19, 2026
★★★★★ 5
You won't be sorry
Size: 10.5-11.5 Women/9-10 Men, Color: Black
Great padding for comfort and terrific warmth. I bought a pair of Acorns 30 years ago and still have them. Updated to a new color and now feel the benefit of newer padding! I used the sizing listed for shoes and like the roominess for thicker sox. Well made and a joy to put on. (Wisconsin)
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Reviewed in the United States on December 25, 2025