This is a rare, high-compression aluminum cylinder head for the Standard 20hp 2.5L 6-cylinder engine. This unit was famously used in the SS1 (1932–1936) and the early SS Jaguar 2.5 Litre models. Unlike the more common cast-iron versions, this aluminum casting was designed for performance-oriented "Special" variants of the pre-war Standard/SS powerplants.

Technical Specifications & Markings

• Engine Fitment: 2.5 Litre (2,522cc) Straight-6 Side-Valve.

• RAC Rating: Stamped "20 HP" indicating the tax horsepower rating.

• Design: Features the Harry Ricardo "Turbulent Head" design with the iconic "heart-shaped" combustion chambers.

• Patent Number: PATENT No 148046-19.

• Casting/Part Numbers: Clearly stamped with BA53812 and 38943.

• Included Accessory: Comes with a vintage Coopers Gasket, part number S6889, which is the correct fitment for this 20hp unit.

Condition Report

• Material: Aluminum alloy.

• Visual Integrity: The combustion chambers and gasket mating surface appear clean and free of major scoring or catastrophic pitting.

• Physical State: All spark plug threads and mounting holes appear intact; however, as with all vintage aluminum components, it is sold as-is.

• Recommendation: While the head looks excellent for its age, professional pressure testing is recommended before installation to ensure internal integrity.

Local Pickup or Insured Standard UPS/Fedex.