Designed for fast road/trackday use, this head gives maximum torque and power while still keeping all the reliability for everyday use. Giving smooth power and economy.
This cylinder head is modified from an "as new delivery miles only" Cooper S spec Head! This has not been through thousands of heat cycles and years of possible abuse. This is a genuine original BMW head. Compare this with others!
Once the valve guides are removed, many hours of fettling and shaping is carried out. The inlet valve seats/throats are increased by 1mm and the exhaust seats/throats increased by 1.7mm. Exhaust ports matched to the (larger) Janspeed exhaust manifold and a large amount of material removed from the "strangled throats", which gives optimum performance while still using standard valves and springs. The new guides are fitted and the seats re cut to give three angles for maximum air flow. The valves are now lapped into their seats and a small amount of necessary chamber work is undertaken. Ready to fit