Three Weber 45 DCOE Carburetors and Warneford Intake Manifold for Jaguar

This is a classic performance setup for the Jaguar XK engine (3.4L, 3.8L, or 4.2L). Moving from the standard twin SU setup to Triple Weber 45 DCOEs on a Warneford manifold is one of the most effective ways to increase horsepower, though it requires precise tuning to get right.

Listing Details

• 3x Weber 45 DCOE Carburetors
• Warneford Aluminum Intake Manifold
• Carburetors Produced in Italy
• Fits 4.2L Inline-Six
• Velocity Stacks
• Throttle Linkages
• Phenolic Spacers

1. The Warneford Intake Manifold

Warneford was a legendary Australian performance brand (often associated with the “Speed Equipment” era).

• Design: These manifolds are “short-runner” designs compared to the long, curved factory manifolds. This improves throttle response and top-end flow but can slightly sacrifice low-end torque.

• Fitment: Because the intake runners are straight, clearance with the inner fender well (especially on E-Types) can be extremely tight. You may need “shorty” air horns (trumpets) or offset air filters to clear the bodywork.

• Linkage: Warneford manifolds often require a specific overhead throttle linkage kit, as the factory SU linkage pulls from a different angle.

2. Triple Weber 45 DCOE Setup

The “45” refers to the 45mm throttle bore. For a street-driven Jaguar, 45s are generally considered the “sweet spot”—40s are too small for high RPMs, and 48s are typically reserved for full-race engines.

Baseline Jetting for a Jaguar 4.2L: If you are buying a used set, you will likely need to re-jet them. A common starting point for the XK engine is:

• Chokes (Venturis): 36mm or 38mm

• Main Jets: 145

• Air Correctors: 180

• Emulsion Tubes: F11 (the standard for Jaguars)

• Idle Jets: 55F8 or 60F8

3. Pros and Cons of this Setup

4. Critical Installation Notes

• Fuel Pressure Regulator: You must install a Malpassi Filter King or similar regulator. Weber needle valves will “flood” if pushed by a standard high-pressure electric fuel pump.

• Heat Shielding: Webers sit very close to the exhaust headers on a Jaguar. Use a heat shield between the manifold and the carbs to prevent fuel percolation (vapor lock) after the engine is shut off.

• Soft Mounts: Always use “Misab” spacers (rubber O-ring seals) and “Cosworth” mounts (cup washers with rubber bobbins) between the carbs and the Warneford manifold. This prevents engine vibration from “frothing” the fuel in the float bowls.

5. Estimated Value (2026)

• Full Kit (Manifold + 3 Genuine Italian Webers + Linkage): $3,500 – $4,800

• Warneford Manifold Only (Rare/Used): $600 – $900

• New Production Webers (Spanish): Approx. $650 each