It might not that unbelievable if he was talking about an 040, they require an oscillator at twice the cpu clock frequency.
Even so i've never heard of anyone running a 66.5 Mhz 040
If anyone can remember fraggle from #gas, circa 1999, he had his apollo 040 40Mhz clocked up to 55Mhz with an 110mhz oscillator from onspec, but never got any faster than that.
