But they don’ t‘ just’ fit. Unbelievably, with twice the number of valves and camshafts, the new heads are smaller and lighter than the factory Porsche units. Not only is there a performance benefit of shaving 3.5kg off the 911’ s rearmounted engine, but the reduced size means there’ s no issue squeezing the motor into any air-cooled 911 shell.
‘ An engine, its vibration, its noise and its RPM have to really come on top.’ For a road car engine, these really are the only important factors. The prospect of having these heads in any classic 911 is so tantalising that, if you had the money to double your Porsche’ s valves, you’ d have to, wouldn’ t you? At £ 37,737 for the basic kit, you’ d need a lot of money, but no one said Porsches were cheap. Especially truly incredible ones. And a 911 sporting heads that have been created for the sole purpose of stirring emotions and creating fun by using ultra clever engineering, that has to be an incredible one.
This four-valve conversion has been deeply considered and elegantly engineered to make it work
42 The Engine Rebuilder Issue 04