FAQ: Is it possible to convert an existing install of Gentoo Linux to Funtoo Linux?
Yes, it is possible, but not supported. Some people have done it, but you should not rely on it to always work. It is always best to install Funtoo Linux by following the steps in our installation documentation. If you proceed to convert an existing Gentoo system to Funtoo, be aware that it may not work, and we will not officially support you if you get stuck, so you may have to install from scratch anyway. However, there are people on the forums or on IRC who might be willing to help you out.