Making a guitar or replacing a neck/body on an existing guitar.
Be sure that you are aware, before starting such a project, that it requires some technical and woodworking skills to complete any project like this. Parts, from any manufacturer are not "universal" and will always need to be fitted together to some degree. This will require at the minimum, files and sandpaper, but may require more extensive tools for completion.
Separate Neck-body type guitars, such as the Fender Telecaster and Stratocaster, have been made for many years, by many, many different sub-contractors in the U.S., Mexico, Japan, Korea and now China - all are different and the guitars have gone through many, many transitions even in the U.S. made guitars - parts do not always interchange or fit universally.
Modern catalyzed finishes are relatively thick, and may need to be sanded down to fit some applications.
It is best to work towards a very tight fit between neck and body, than to have them fit together instantly and loose. The tight fit will have better sustain and help to overcome the inherent structural losses of a bolt-on neck.