Named Tintin: Yeah, that's propably the case with a larger head. Even with 9mm head it feels that it is just on the "edge". I think no more shimming could be possible.
I did Tintin's method. I haven't had a chance to try it because my injector return lines are leaking so much that they would probably fly off if I redlined it. Unfortunately I won't be able to try it until I get new hoses.
The main spring determines when the engine will cut-off at high RPM, it is only that it which should be hardened or shim, the intermediate spring is already completely compressed around 2000rpm ( that depend of the model of pump), if you put it harder the intermediate spring, not only that gives absolutely anything, the RPM will be hard to control at low RPM, the car will make shudder in first and second gear at 1/4 throttle, and the high RPM cut off will not be changed.
So is that why when not in gear, if I give a little throttle, the engine speeds up a little, then the rpms quickly rise without further pedal movement? I may have to undo my intermediate spring mod, if I can find where I put the spring....