Re: Soon to be a New Norinco MAK 90
congrats !! not sure what you mean by upgrading. if it's a post ban configuration it will have a thumbhole stock and no muzzle device. to replace the stock you'll need to see if the receiver's back end is straight or angled. not much you can do about the castrated muzzle brake other than tapping for some sort of aftermarket flash hider. if it's a single stack mag (which i doubt) you can open the magwell by hand to accept a double stack.
actually, you're getting a rather nice AK to begin with so don't mess with it too much. enjoy !!
take a kid shooting... they are the next vote