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- USA
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Ships within 48 hours · Estimated delivery Jul 8 - Jul 13
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Description
500 CFM Ultra XP 2BBL Carburetor - 0-4412HBXOverview: The original Holley 0 4412 has powered thousands of racers to the winners' circle! How do you make it better? Add the proven design elements of the popular Ultra series for more tunability, more durability, more weight savings and more features! The Ultra XP 2bbl carburetors feature all aluminum construction for nearly 50% weight savings over their zinc counterparts, contoured venturii inlet for unobstructed airflow, screw in air bleeds for
Overview:
The original Holley 0-4412 has powered thousands of racers to the winners' circle! How do you make it better? Add the proven design elements of the popular Ultra series for more tunability, more durability, more weight savings and more features! The Ultra XP 2bbl carburetors feature all aluminum construction for nearly 50% weight savings over their zinc counterparts, contoured venturii inlet for unobstructed airflow, screw in air bleeds for easy fine tuning, black anodized fully adjustable billet aluminum metering block and baseplate, high capacity fuel bowl which features 20% more fuel capacity to eliminate starvation, integrated fuel shelf to minimize fuel aeration and internal baffling to control fuel slosh and a centered air cleaner flange for improved airflow and performance. Other notable features include wedged floats, knurled hand adjustable curb idle screw and down leg boosters. Ultra XP 2bbl carburetors are approved for use in NASCAR® Mid-West/West Coast Late Model Divisions and utilize the same venturii and throttle bore dimensions of the classic 4412 2bbl carburetor. Available in shiny or Hard Core Gray finishes, the Ultra XP 2bbl will outperform any production 2bbl available.
Features:
- All aluminum construction - for nearly 50% weight savings over zinc version
- Hard Core Gray with Black™ billet aluminum metering block and base plate
- No choke tower for unobstructed airflow
- Air bleeds moved outward to allow a smoother transition of airflow
- Air cleaner flange centered over venturii for improved airflow and performance. 5/16-18 bent air cleaner stud included
- Down-leg boosters for improved fuel signal
- Contoured hex head squirter screw for streamlined airflow
- Internal pump passage on metering block equipped with tunable bleed off
- Same 1-3/8” Venturii & 1-11/16” Throttle Bore size and Throttle Plate/Throttle Shaft size of original 0-4412
- Fuel bowl provides 20% more fuel capacity while controlling slosh with internal baffling
- Clear sight windows on both sides of bowl for easy & safe fuel level adjustments
- Fuel trough designed into floor of bowl to route fuel flow directly to the jets and assists in keeping jets covered by fuel
- Built in drain plug provides easy access to empty contents of bowl
- -8 (O-ring) inlet threads offer a large variety of plumbing options (come with an extended -8 O-ring to -8AN male adapter and -8 plug). Can be plumbed from either side
- Throttle shaft rides in oil impregnated sintered bronze bushings for smooth throttle actuation
- Throttle shaft capped to prevent entry of debris & contaminates
- 30cc pump with metal lever. Anti-siphon valve in mainbody to reduce pump pull over
- Dedicated race-only throttle lever with all unnecessary street attachment points & tangs removed
- Knurled (hand adjustable) curb idle screw allows for easy idle adjustment without the use of tools
- Set screw for wide open throttle stop adjustment
- Wedge float provides fuel control while cornering
- 100% wet-flow tested by Holley technicians to assure it arrives ready to run!
Application:
| Year | Make | Model | Submodel | Engine Size |
|---|---|---|---|---|
| Universal |
Specs:
| Barrels | 2 |
|---|---|
| Billet Color | Hard Core Gray with Black |
| Booster | Down Leg |
| Brand | Holley |
| Carburetor Use | Performance and Race |
| CFM | 500 |
| Choke | None |
| Condition | New |
| Emission Code | 3 |
| Finish | Hard Core Gray |
| Fuel | Gasoline |
| Fuel Inlet | Single |
| Marine Use | No |
| Material | Aluminum |
| Model | 2300 |
| Primary Main Jet | 74 |
| Primary Power Valve | 3.5 |
| Primary Pump Nozzle Size | 28 |
| Product Type | Carburetor |
| Secondaries | None |
| Supercharged Application | No |
| Throttle Bore | 1.688 inch |
| Venturii Size | 1.376 inch |
| Warning | California Proposition 65 |
| Warranty | Limited 90 Day |
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
4.8 ★★★★★
Based on 111 reviews
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Product Reviews
★★★★★ 5
One of the best dog toys I’ve bought off Amazon in a long time
Color: Green
My dog Rosie is a heavy tower so it is difficult to find balls she doesn’t destroy quickly. I came across this item on Amazon and it is honestly one of the best pet toys I’ve ever bought on Amazon. After a long day of work sometimes I come home and Rosie has a lot of energy. I turn this ball on fast mode and she has so much fun. I do worry about how much shaking in her mouth. I don’t wanna give her a headache, lol but there’s also a slow mode that you can press for the ball to slowly move around, but it’s a really good toy and I’m happy. I purchased it if you have a heavy tower, I wouldn’t worry about them breaking it because we’ve had it for a couple weeks now and she’s doing great.
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Reviewed in the United States on March 15, 2026
★★★★★ 4
Not indestructible, but dogs love it
Color: Green
My dog LOVES this toy. Unfortunately, she loves it so much she destroys it. I have now purchased FOUR of these, but if left unattended for 5 minutes, my American terrier breaks this apart. She loves it so much though, I keep buying replacements. This is a wonderful enrichment toy, but you must keep an eye on your toothy friend.
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Reviewed in the United States on December 29, 2025
★★★★★ 3
Engaging and Fun, But Lacks Durability for Strong-Gripped Dogs
Color: Green
The internal mechanism of this toy works very well, and the ball’s movement immediately caught the attention of my Boxer pup. He was absolutely fascinated and spent hours each day playing with it. However, while the toy’s design is engaging, the durability of the exterior leaves much to be desired—especially for dogs who tend to pick things up with a firm grip.
We didn’t know what to expect since our pup hadn’t previously played with an interactive ball, so we supervised playtime and made sure to store the ball in a safe spot when we couldn’t keep an eye on him. Despite this, the ball didn’t hold up. Our pup wasn’t intentionally chewing it. He simply carried the ball in his mouth when we moved downstairs or to another room, yet the grip while he carried the ball caused significant damage to the exterior. Within about a week of regular use (approximately 40 hours in total), the ball’s outer layer became deeply gouged by his teeth.
To clarify, my pup wasn’t biting down hard or trying to destroy it, but his natural grip while carrying the ball left deep grooves in the surface. In just days, these gouges made the exterior sharp to the touch and compromised the structure. By the end of the week, we couldn’t screw the cover back together after removing it to recharge the ball, which made it unusable. And I was dismayed that there aren’t replacements readily available.
Overall, my pup absolutely loved this toy — it was engaging and kept him entertained for hours. However, if your dog has a strong grip or frequently carries toys in their mouth, this may not hold up as well as expected. It’s a great concept but needs a more durable outer layer and replacement hard covers to make it a long-term investment.
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Reviewed in the United States on January 3, 2025
★★★★★ 5
My dog loves this ball
Color: Green
The battery on this lasts forever. The random on/off motion and when it gets touched inducing motion just keeps my dog guessing and occupied for a long time. My dog's tail is wagging the whole time.
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Reviewed in the United States on May 5, 2026
★★★★★ 5
Great ball
I have bought two of these in different colors. My Yorkie loves them. They’re very interactive even if you don’t put the cover on it they move and if he’s not playing with it, it tends to go into sleep mode.My Yorkie got the cover off the ball within the first two minutes. But he loves the ball. Now bought 2nd ball. The ones with covers don’t work he rips the covers off.
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Reviewed in the United States on October 15, 2025
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