[fred cook]

About 2 years ago I built a 3.3SS engine for my SC. It is using 10.1:1 Mahle pistons, KN Engineering 100mm cylinders, 964 cams, Carerra twin plug heads, Electromotive XDi direct fire ignition, CIS induction, etc, etc, etc. As you can see, it is quite similar to the engine in your car except for the intake system. However, my engine will pull like crazy up to the ignition cutout at 7500 rpms. So, it does seem that your engine is restricted somewhere. There is an old saying among hot rodders that the horsepower is in the heads. Since you have the big (48mm) ITBs, hot cams, and direct fire ignition, you might consider the following: 1) Ports in the heads are too small or not matched to the intake diameter, or 2) you are not providing enough amperage to the power for the direct fire coils. If it's the first, it's a case of trying to pull air over a ledge that is causing non laminar flow to the intake ports. The intake size and cylinder head port size should be the same for good flow. If it's the second, then your ignition system just can't supply the spark intensity needed to make power at high rpms. The coils should be operating off of relays that pull current directly from the battery. As a general rule of thumb, expect to need 1 amp of current for each 1000 rpms. So, your system would need to provide 7-8 amps to each coil pack for max power. Happy hunting and good luck!