holley
Holley 12278 Standard Carburetor Main Jet
- SKU:
- 19486354
- MPN:
- 12278
- Availability:
- Usually ships the same or next business day. In stock at our PA, TX warehouses.
- Shipping:
- Calculated at Checkout
- Stock Update:
- 09/07/2026 12:32:53 AM PST
Bulk discount rates
Below are the available bulk discount rates for each individual item when you purchase a certain amount
| Buy 2 | and pay only $19.69 each 19.69 |
| Buy 3 | and pay only $18.27 each 18.27 |
| Buy 4 or above | and pay only $17.35 each 17.35 |
- Stock Update:
- 09/07/2026 12:32:53 AM PST
Frequently bought together:
Description
This item is brand-new, factory sealed.
Holley 122-78 Standard Main Jet - Pair- Designed to fine-tune the carburetor for street or race applications
- Threaded for easy installation and removal
- 0.0870'' hole size
- Comes with 1/4-32 unified fine thread
- Comes in a pair
- Manufacturer: Holley
- Brand: Holley
- Model: Holley Carburetor Standard Main Jet
- Item Weight: 0.352 ounces
- Country of Origin: USA
- Item model number: 122-78
- Is Discontinued By Manufacturer: No
- Exterior: Machined
- Manufacturer Part Number: 12278
- OEM Part Number: 122-78
This standard main jet is manufactured to high tolerances for consistency and is designed to fine-tune the carburetor for street or race applications. The hole size measures 0.0870'' and is threaded for easy installation and removal. It is a replacement jet and comes with 1/4-32 unified fine thread.
Warranty Information
All Items are Brand New, Factory Sealed and come with a standard warranty. [Read our policies]
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Holley 12278 Standard Carburetor Main Jet
$26.04