The rpm's Campy was talking about (re: ringed engines acheiving less than ABC types) isn't the rated maximum RPM's, but what that engine will achieve with the same fuel and prop as another.

You might have a ringed 40 and a non ringed 40, both by the same mfr (for arguement's sake). You might feed both Omega 15% and have 'em spin a 10x6. The ringed engine might manage 12,000 rpm once it's broken in, while the ABC might be doing 12800 with the same stuff.

The stated maximum rpm's are given as a guideline. You can expect that the engine will not come appart immediately up to that speed. Much like the redline on your car, you don't aim to achieve it (often).

J