>>1815483i was expecting a pic of the model
> I've never done a headswap beforedoing a head swap is easy anon, it's just a matter of practise, so don't get mad if at first you didn't make it
do this:
erase all the materials, physics and rigid bodies that aren't part of the head and/or hair, as well as their bones, except the two neck bones
then in the body do the inverse and keep the two neck bones, after that import the head and it should be done.
sometimes the head will be too small or too low to the neck when you import it so i advise you to move the head first, then you save, and then you open the body file and import the head and move it to the neck,
also se the S button in pmd view window to see another window that would serve as an preview without the vertex and stuff, while you use the pmd view window as the workshop, also click the last button on the right, it would divide the viewer into four: free, top, side and front view and work with side and front view while headswaping, since you only need to change the values of Z and Y.