How to add 24 valves and 12,000 rpm to your classic 911

A new cylinder head kit from Britain’s Swindon Powertrain gives a mighty boost to 964- and 993-chassis, air-cooled Porsche 911s.

The company’s M64 head adds an extra two valves per cylinder and is said to “unlock substantial increases in both power and torque.” Swindon Powertrain’s testing shows that inlet peak flow is increased by 40 percent while exhaust peak flow is upped by 66 percent.

The new head is cast from A356 aerospace-grade aluminum and the heads and cam chests are CNC-machined by the company that built engines for the last three British Touring Car Championship winners. It weighs around seven pounds less than the original 993 unit as well.

In addition to the head, there are titanium inlet and exhaust valves with springs, caps, collets, shims, finger followers, and shafts, plus camshafts, cam covers, and timing drive input. Extra options include a power steering drive to enable the use of the 993’s production system, custom pistons designed to take full advantage of the increased breathing efficiency, inlet porting, and bespoke cam profiles.

Opt for all the goodies and your 964 or 993 will safely rev to 12,000 rpm!

“Factory cylinder heads traditionally held back worthwhile gains for the traditional oversquare Porsche air-cooled flat-six engines,” says Raphaël Caillé, managing director at Swindon Powertrain. “Our extensive research and development programme enabled us to eliminate the compromise to create arguably, the ultimate cylinder head for an air-cooled 911. Using the latest innovations in materials alongside CNC machining to F1 tolerance standards, our cylinder heads transform an air-cooled engine. The improved breathing and ability to rev, unleash the potential to experience your 911 like never before.”

The kit costs £29,950 ($36,300) plus taxes and comes with a 12-month warranty.

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