yeah that book is junk. I got it when it came out. All the info on it is way outdated. I knew more about the motor than what is in the book. And that was years ago. Some of the companys in that book are no longer in business so that would make it fun to try and get the parts from them.
I agree there is better info here than what can be found in that book. My understanding is that most cam companys use 1.6:1 some use 1.7:1 because it's close to the actual rocker ratio. But to me it means you have to know the advertised ratio as well as the actual in order to correctly size up the lift at the valve to avoid coil bind.