Bollen,
I used values I personally have tried with dynos as well as everyone submitting info to me for the calculations.
It is pretty accurate you will find. The only places where it may be a little off is with modded stock pipes (due to varied backpressures) and drilled airboxes, again due to differences in hole size and such) But still accurate enough.
This is for the 790 270º motor by the way. BUT Some folks have told me that they have used it with success for the 865 270º motors as well.
If I had addiditonal information form the regular Bonnie guys and the 865cc guys, I could add to it to fine tune even more.
But at this point in time, I think it is adequect.
