My top speed in my first 120y was 142kmh at 7000RPM.
I used to rev my mildly rebuilt a12 to 8000, but it didn't really acheave anything.

As for the ca18 going around the clock twice, that doesn't sound right. I bought a 120y with a ca18 DET from adelade and when driving back to Melbourne got up to between 180 - 190 kmph and the speedo only went round once to 0. Only reason I know the approx speed was because my friend was driving his Ford Terriroty and he was going about 200 and I was behind him.