The LG Optimus G has received its own taste of Android 4.4 KitKat courtesy of an unofficial source based build. The source-built ROM currently is a vanilla AOSP-based build. However, as time goes on and the Paranoid Android team updates the PA sources to work with KitKat, the builds will evolve into official Paranoid Android and bring you all of the layout and dpi features you know and love.The ROM itself is natively compatible with the E970, E973, and E971 versions of the device. However, it can also work on the E975, E976, and E977 if you flash an alternative kernel after flashing the ROM. The early builds lacked WiFi and external SD card support, but these have now been fixed as of the latest revision. Most users are reporting a relatively flawless overall experience.
So if you own an LG Optimus G and don't want to wait for the official KitKat update to be rolled out by LG, just follow the source link to the ROM and get started on bringing KitKat to your device.
source - XDA Developers