How to convert 1/10 motor kv to 1/8 motor?

[superek4]

Need help if possible, I m using a novak brushless final gear ratio guide. It tells me if my 1/10 cars are under or over gear. I Like to apply to my 1/8 electric cars. But the motors in the guide comes in 3.5,4.5,5.5 n so on. The kv of the motors are alot higher too.

Is there a way to convert the 1/10 motor's kv to 1/8?

Hope it's not too confusing:)