Holley Screw-In Main Jet Extensions (Pair)
Holley Screw-In Main Jet Extensions (Pair)
Part Number: 122-5000
Holley Screw-In Main Jet Extensions (Pair)
Eliminate high-G fuel starvation and lean engine conditions during extreme acceleration, heavy braking, and hard cornering with authentic Holley main jet extensions.
Product Overview
Engineered for high-performance drag racing, circuit racing, and hard launch applications, the Holley 122-5000 main jet extensions move the main metering jet fuel pickup deeper into the fuel bowl. By relocating the fuel entry point, these brass extensions ensure your jets stay submerged in fuel under severe inertial forces, preventing dangerous lean conditions that can compromise engine performance or cause internal damage.
Designed to screw directly into standard Holley 1/4″-32 threaded metering blocks, these extensions accept standard Holley main jets at their outer end for straightforward installation and tuning flexibility.
Key Features
- ☑ Anti-Starvation Design: Prevents fuel sloshing from uncovering main jets during hard launch or braking.
- ☑ Direct Screw-In Fitment: Threads directly into Holley metering blocks with 1/4″-32 pitch threads.
- ☑ Precision Brass Construction: Machined from high-grade solid brass for durability and fuel resistance.
- ☑ Standard Jet Compatible: Accepts all standard Holley main metering jets at the extended end.
- ☑ Motorsport Proven: Essential upgrade for high-G motorsport applications, drag strip setups, and track cars.
Technical Specifications
| Brand | Holley Performance Products |
|---|---|
| Manufacturer Part Number | 122-5000 |
| Product Type | Carburetor Main Jet Extensions |
| Material | Brass |
| Metering Block Thread Size | 1/4″-32 in. |
| Carburetor Compatibility | Holley 4150, 4160, 4500 (Dominator) & compatible Demon carburettors |
| Float Requirement | Requires notched float (e.g. Holley 116-11) for clearance |
| Quantity | Pair (2 Extensions per Package) |
What’s Included in the Box
- 2x Holley Brass Screw-In Main Jet Extensions (PN 122-5000)
As an authorized UK supplier of genuine Holley motorsport hardware, JP Racing offers complete technical support and fast UK dispatch. Maintain precise air/fuel ratios on track with trusted Holley fuel system components.