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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 - 0-4412BKXOverview: 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
- Tumble polished aluminum 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 | Shiny with Black Billet |
| Booster | Down Leg |
| Brand | Holley |
| Carburetor Use | Performance and Race |
| CFM | 500 |
| Choke | None |
| Condition | New |
| Emission Code | 3 |
| Finish | Shiny |
| Fuel | Gasoline |
| Fuel Inlet | Dual |
| 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
4.1 ★★★★★
Based on 1927 reviews
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Product Reviews
★★★★★ 5
Read this review. This pillow saved me.
Size: Standard/Queen (Pack of 1), Style: High Loft (6"-7")
I have to testify about this pillow, my brothers and sisters. Ever since I hit my 30s, my body has gone down. Aches and pains. Pops. Crackles. Snaps. It’s ridiculous. Over the last 2 years, I have managed to injure a muscle in my shoulder and the pain is unbearable when it is inflamed. I finally narrowed it down to the pillow I was sleeping on. I have an attachment to a pillow I’ve owned for over 20 years - that’s another story. I could fold it 3 times and it was finally thick enough to support my head. My shoulder got so tore up recently that I had to go through 2 rounds of steroids plus round the clock ibuprofen. Waking up in the night, the whole ordeal. I ordered this pillow after much research all over the internet. I was appalled by the $165 price ticket. But when you’re in that level of pain, you’re just about willing to do whatever it takes. The first night I immediately noticed I got more consecutive hours of sleep than I had in weeks. A week later and my shoulder is pain free. I could’ve cried. The height of this pillow stabilizes my neck and shoulders perfectly. It is firm, but gives and contours to your neck and head. It’s a heavy pillow but I don’t even care. Truly I don’t think I’ll ever go back. This pillow has saved my shoulder and I’ll never stop thanking God for it. If you’re experiencing back, shoulder, or neck pain and are considering this pillow, just order it. Please. Just do it. I’m forever changed. But I’m still keeping 20 year old pillow… just for sentimental purposes. 😂
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Reviewed in the United States on September 3, 2025
★★★★★ 5
Really good pillows
Number of Items: 1, Number of Items: 1
I’ve been using this pillow for a while now and it’s honestly one of the most comfortable pillows I’ve tried. It has a soft, cloud-like feel but still gives enough support for my neck and shoulders. I’m a side sleeper and it keeps its shape well through the night. The material feels high quality, and it doesn’t go flat like cheaper pillows. Definitely improved my sleep quality and worth the purchase.
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Reviewed in the United States on May 12, 2026
★★★★★ 5
Soft AND supportive
Number of Items: 1
I knew I needed a very soft pillow - all the foam pillows I had bought recently to try to upgrade our home pilllow selection seemed ok to the touch but were still too firm once I tried them out, but recently I also had some neck pain that needed some gentle support and the old old foam pillow I had that was so very soft was losing its supportive qualities and the pain wasn’t getting better. This one seemed by description to fit the bill- very soft by the company’s own definition but also with support. I’m happy to report this is exactly as advertised- the softest foam pillow I’ve tried out of the box but also good support. Pain has improved since I started using this pillow. I would buy more if we need more pillows, it’s perfect for me and I think would be comfortable for most people. I think you just need to figure out how firm you need your pillow and also height preference . I’m an all over sleeper -back, side, even belly sometimes, so it’s fine for me, but it is a little taller compared to other pillows I’ve bought recently. I didn’t compare/try other prominent pillow brands, mostly my experience is Ikea (my daughter uses a very flat and nice foam pillow from them that is even a little pricier than this one and it works well for her), and whatever brands happen to be available at target and Costco. This price point for a name brand is reasonable, I think; I was looking at other brands way over $100, and I was willing to spend that much for something that would work long term, so this one working was great. Also, this definitely does not have any cooling effect technology, which is fine by me, but something to consider if you do like cool pillows. (Although, PSA: I recently had to throw away older foam pillows that had those cooling gel panels because the gel panels started disintegrating into sticky ooze; gross and had to throw away whole pillow because couldn’t dissociate from rest of the pillow. Sad cuz the foam part of those pillows were fine.) Anyway, if you like softer pillows but want good support, this one works well and is worth trying!!
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Reviewed in the United States on May 30, 2025
★★★★★ 4
Flatter than a regular pillow but nice and soft
Number of Items: 1
Is it softer than a typical memory foam pillow? Yes. But it’s also a lot flatter. I don’t find this pillow rebounds very well. It’s good for stomach sleepers but not so much for side sleepers. I’m a 2/3 of the night side sleeper so it’s unfortunately not my magic pillow.
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Reviewed in the United States on February 11, 2026
★★★★★ 5
Best pillow for my neck pain.
Number of Items: 1
I've tried so so many pillows to relieve my neck pain at night and this one is the first pillow that has actually worked. I was skeptical at first as this pillow is heavy and dense but one night and I was hooked. I couldn't believe I found a pillow that actually not only was comfortable but also relieved my neck strain. It's worth the cost to now be able to wake up without pain.
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Reviewed in the United States on May 8, 2026