HOLLEY 6478 Double Pumper Carburetor Block 4150 4778-1

( Brand: Holley ), ( Type: Metering Block ), ( Manufacturer Part Number: 6478 ), ( Performance Part: Yes ), ( Universal Fitment: No )

Review HOLLEY 4150 Double Pumper Carburetor Metering Block List

The Holley 6478 4150 Double Pumper Carburetor is a high-performance fuel delivery system designed for serious hot rods and muscle cars. This carburetor is part of Holley's Ultra series, which offers improved idle quality, enhanced drivability, and increased power.

The 6478 model is a 2-barrel carburetor, specifically designed for engines with a displacement between 350 and 500 cid. The 4150 series refers to the size of the primary and secondary venturi, which measures 4150 cfm 700 rpm.

The Double Pumper design features two independent fuel pumps, each with its vacuum secondary. This setup provides superior fuel pressure and delivery, resulting in improved engine response and power. The secondary pumps engage at low engine vacuum, ensuring a consistent fuel supply during acceleration and cruising.

The carburetor block, part number 4778-1, is the base component that houses the carburetor elements. It is machined from high-quality aluminum and features a polished finish, adding a touch of style to your engine bay. The block is designed to be a direct replacement for the stock carburetor on most applications, making installation straightforward and hassle-free.

The Holley 6478 4150 Double Pumper Carburetor is engineered for durability and performance. It comes with a variety of factory-installed options, such as a vacuum secondary system, electric choke, and adjustable idle mixture screws. The carburetor also includes a full set of gaskets, hardware, and instructions to make the installation process as seamless as possible.

In summary, the Holley 6478 4150 Double Pumper Carburetor is a high-performance fuel delivery system that offers improved idle quality, enhanced drivability, and increased power. The 2-barrel design is suitable for engines with a displacement between 350 and 500 cid, and the Double Pumper setup ensures consistent fuel delivery for optimal engine performance. The carburetor block is made from high-quality aluminum and is designed for easy installation on most applications.

The Holley 6478 4150 Double Pumper Carburetor is a popular choice among hot rodders and performance enthusiasts due to its ability to deliver large amounts of fuel to high-performance engines. Here are some pros and cons that might help you make an informed decision about purchasing this carburetor:

1. High-performance: This carburetor is designed to deliver large amounts of fuel to high-performance engines, making it an ideal choice for hot rods, muscle cars, and other high-powered vehicles.

2. Double Pumper: The double pumper design allows for increased fuel flow and better fuel pressure, which can lead to improved engine performance and power.

3. Adjustable: This carburetor comes with adjustable features, allowing users to fine-tune the air/fuel mixture for optimal engine performance.

4. Durable: Holley carburetors are known for their durability, and the 6478 4150 is no exception. It is constructed of high-quality materials and is built to withstand the demands of high-performance applications.

5. Wide Application: This carburetor is suitable for a wide range of applications, including both gasoline and alcohol fueled engines, making it a versatile choice.

1. Complexity: Compared to single-barrel carburetors, double pumper carburetors can be more complex to install and tune, requiring a greater amount of expertise and time.

2. Cost: The Holley 6478 4150 Double Pumper Carburetor is more expensive than many single-barrel carburetors, which may be a deterrent for some buyers.

3. Size: Due to its high-performance capabilities, this carburetor is larger than many single-barrel carburetors, which may be a concern for those with limited engine bay space.

4. Maintenance: Double pumper carburetors require more frequent maintenance than single-barrel carburetors due to their complexity, which can be a drawback for some users.

The Holley 6478 4150 Double Pumper Carburetor is a high-performance carburetor that delivers large amounts of fuel to high-performance engines. It comes with adjustable features, is durable, and is suitable for a wide range of applications. However, it is more complex and expensive than many single-barrel carburetors, and requires more frequent maintenance. Ultimately, the decision to purchase this carburetor depends on your specific needs, expertise, and budget. If you are looking for a high-performance carburetor and have the expertise and resources to install and tune it, then the Holley 6478 4150 Double Pumper Carburetor may be an excellent choice for you. However, if you are looking for a simpler and more affordable option, then a single-barrel carburetor may be a better choice.

If you are looking for a high-performance carburetor and have the expertise and resources to install and tune it, then the Holley 6478 4150 Double Pumper Carburetor is an excellent choice. However, if you are looking for a simpler and more affordable option, then consider a single-barrel carburetor. Alternatively, you could also consider an electronic fuel injection system, which offers even greater fuel delivery capabilities and ease of use. Ultimately, the best choice depends on your specific needs, expertise, and budget.

part # 6478 prices

• $40.00-$150.00

specifications carbcaddie:

• brand: Holley
• type: Metering Block
• manufacturer part number: 6478
• performance part: Yes
• universal fitment: No

shipping carbcaddie:

• transit: 2-6 Days
• class: Standard, One-day, Expedited
• type: Calculated
• carrier: UPS
• cost: $10.96
• service: UPS Ground, UPS Next Day Air Saver, UPS 2nd Day Air

seller carbcaddie:

• # reviews: 907
• rating: 100.0%

returns carbcaddie:

• policy: Returns Accepted
• time: 30 Days
• paid by: Buyer

offer carbcaddie:

• quantity: 1
• availability: In Stock
• options: Ship-to-home
• started: October 29, 2025
• sold: 0

general carbcaddie:

• condition: Used
• Car Truck Parts Accessories > Air Fuel Delivery > Carburetor Parts

payments carbcaddie:

• other
• wallet: Paypal
• credit card: Visa

Holley 6478 Is Similar To:

• Ford D0of-9510-n 1970 Cobra Jet 429 Scj Manual 4 Speed Holley Carburetor List 4627 As Is (32.1% similar) $223.99–$2672.99. (August 23rd, 2024)
• Holley 12r-5204b Carburetor Throttle Base Plate #0559 (43% similar) $19.00–$190.68. (August 23rd, 2024)
• Holley 12r-4251b Carburetor Throttle Base Plate #0574 (44.6% similar) $24.95–$58.63. (August 23rd, 2024)
• Holley 3887686 2 Bbl 500 Cfm Marine Carburetor Volvo Penta 4.3l For Parts Or Rebuild (42.1% similar) $159.99–$650.00. (August 23rd, 2024)
• Holley 12r-4507b 650-800 Dp Double Pumper Base Plate Baseplate 4160 4779 4777 4778 4780 (50.3% similar) $80.00–$199.99. (August 24th, 2024)
• Holley 36-181 Carburetor Metering Jet 2 Of Each Size Contact Prior Ordering (44.8% similar) $88.00–$98.45. (August 24th, 2024)
• Holley 5583-4519 1968 1969 Metering Plate 5583 For 4053 4346 Chevelle Camaro 396 427 Copo (33.1% similar) $999.99–$1499.99. (August 24th, 2024)
• Holley 8485-1947 Primary Front Metering Block 18502 600 Vacuum Secondary Carburetor (43.7% similar) $25.00–$199.00. (August 24th, 2024)
• Holley 7115 Primary Front Metering Block 6510 Spread Bore 650 Vacuum Dp (48.9% similar) $249.74–$1750.00. (August 24th, 2024)
• Holley 37-1536 Carburetor Renew Kit 4160 (55.6% similar) $119.99–$218.35. (August 25th, 2024)
• Holley 80457-2 List Carburetor 600cfm 4bbl 4160 Main Body Only With New Gasket (35.6% similar) $8.35–$11.25. (August 26th, 2024)