Well on My Norinco I changed the bolt, had a lot of trouble with the orginal, the firing pin was to long and was punching through my brass, then the brass shavings would jam the pin. I got a HNR bolt assembly complete out of the USA. had that installed, shimmed the gas return, as I was having cyclying problems.Problem solved, Now she feeds, fires and edjects 100%.
Change the op rod spring, or opr rod if your so inclined. I kept the orginal opt rod and she shoots like a champ. The stock for sure must go, but other than those few things its great the way it is. Just be senseable, The Norinco is a low cost clone of the M-14. The quality is fare, there are some things that my need adressing, to make it a good reliable shooter. But as for as dumping endless mods into one, well its a loosing return. If you want a superstar m14 go buy a National Match Springfield. But as for just a standard M1a I would buy the Norinco. I have about $1000 in mine, but most of that was the bolt price and the gunsmithing and magazines. A far cay from the $1800 plus Tax for a standard M1A.
So good luck on your project.