Classic Mini Unleaded Cylinder Head 25cc chamber size for 1380cc engine block – Fast Road / Track Spec (9-Stud)
Unlock serious performance from your Classic Mini or Moke with this fast road / track-ready large valve cylinder head, engineered to deliver maximum horsepower and torque while maintaining excellent drivability.
Developed using proven airflow bench and dyno testing, this head is optimised for modern fast road and road/rally camshaft setups—making it the perfect choice for enthusiasts who want real-world performance gains.
Key Features & Specifications:
Road Sport Performance Cylinder Head (Big-Bore A-Series)
This high-performance cylinder head is developed from carefully selected used core castings and re-engineered in true Road Sport specification. The focus is on maximising real-world drivability, delivering strong torque characteristics and smooth power delivery across the rev range when paired with mild to fast-road camshaft profiles.
Key Specifications
- Valve sizes: 35.6mm inlet / 29.3mm exhaust
- Valves: Chrome-stem MG Metro specification (35.7mm inlet / 29.3mm exhaust)
- Valve guides: High-quality cast iron
- Valve springs: Double springs rated at ~180lb (at max lift)
Maximum capability:
- Up to 6,500 RPM continuous
- Up to 0.475" valve lift
- Combustion chamber volume: Approx. 24–25cc (ideal for 1360, 1380 & 1400cc engines)
- Configuration: 9-stud fitting as standard
Stage Classification (Traditional Tuning Reference)
Following classic Special Tuning philosophy rather than generic labeling:
Stage 1:
33mm inlet / 29mm exhaust – standard valves, gas-flowed Stage 2 (Road Sport – this head):
35.6mm inlet / 29mm exhaust – road-quality valves, ported for road performance Stage 3:
35.7mm inlet / 29mm exhaust – race-quality valves, Super Sport/Grand Tourer spec Stage 4:
As Stage 3, but with larger valves and more aggressive port/throat modifications
Fitment & Compatibility
Heater take-off port open Bypass hose adapter fitted Both can be blanked for post-1992 applications
Engineering & Performance Features
Port shapes and dimensions optimised for enhanced torque output Valve throat profiling matched to road and fast-road camshaft characteristics Compression ratios tailored for modern unleaded fuel Fitted with genuine AE lead-free exhaust seat inserts Designed for durability and sustained high-performance road use
At Mini World Australia, we focus on parts that actually deliver results—not just claims. This cylinder head is built for drivers who want real, usable performance on the road or track.
Serious airflow = serious power.
