I don't think the 964 cams are all that radical - but Steve is certainly correct in general terms.
Apart from drivability issues (ie., loss of low rpm torque) the limiting factors as to what cams you can run in a 3.2 are (as I see it) threefold:
1. Valve/piston clearance - std CIS/Motronic pistons are fairly high dome. Ideally you want deep valve pockets in the pistons.
2. Common plenum induction - the airflow meter in the single throttle body intake manifold cannot cope with the pulses generated by large overlap cams.
3. High rpm weakness - to get the most from radical cams you need to pull higher revs. As a minimum you want stronger rod bolts, valve springs and valve retainers if not the full Carillo rod package.
If you solve all these problems - ie., RSR style JE pistons, Carillo rods, Raceware valves, springs and retainers, S type cams, individual throttle bodies, twin plug, SSI type exhaust and bespoke engine management - you have a motor producing 320hp at 7000+rpm. You also have a hole in your wallet to the tune of about £20k. Then again, if your car is a bit of a lightweight you have a power to weight ratio close to a new GT2 [
].
Richard
