how do i resize a character body part without changing clothing scale?

so uhh im making a among us type of script need a kill animation that gets rid of the upper body part of an r6 without changing clothing scale, got a gyazo image of my method of doing it (learned it from Rufus14's chainsaw tool)

the thing is, it only works on the block body or in better context, the default package because it makes it so you can see inside the torso if i dont add a part that covers it up, the method works but sometimes you can see inside the torso and bodymeshes wont work,

if anyone can help me with this i would appreciate it.