Just got a Norinco MAC-90 in excellent condition (for an ugly Chinese AK clone ). Based on internal parts condition, I doubt the rifle had more than 50 rounds fired since new.
I understand these rifles are getting harder to find and may have some collector value. I may sell it sometime later for a little profit but I may keep it too. Do you guys think the value will be ruined if I thread the barrel, install a nice muzzle brake and also replace the stock to make it look more like an AK?

I don't know if I got a good deal but I paid $875 for the rifle. It came with 10, like new, East German, 30 rd. mags and 3 mag pouches. I figured the mags alone cost close to $300.

That's a deal for everything, just the rifle that is a bit on the high side ( i have been out of the market for awhile though) ban states like CT can still accept and "deban" them to own an AK type rifle.

If you are looking to deban it here you go, if you ha e any questions let me know...https://www.ar15.com/forums/ak-47/Norinco-MAK-90-FSB-Replacement-Deban-Barrel-Threading/64-158838/

I have debanned many, I still have one in my collection and I absolutely love it. They are great shooters. I love the taco triggers for them and they are CHEAP.

Thanks. I guess it has no collector value. I may thread the muzzle and replace the stock then. Just need to figure out if any original Russian, wooden AK stocks will fit the gun. I don't want any plastic on the gun.

Hard to say, not sure you got a great deal unless you wanted one. I have two that i consider to be collectable. But they are caught in transit ones that have their front fangs, accept the cleaning rod and the original bayonets, and have threaded barrels.  I have bayonets for both of them. Ones chinese the other is an eastern european that required a bit of fitting. One i got unfired the other has been fired but not a ton. I paid 500 for each of them. I have also seen years ago a norinco that was pump action. Gas system wasnt functional. I didnt buy it but i would say its got some collectable value to it. They wanted 350 for it if i recall correctly. Think that was 9 years ago.

They are quality guns. I picked up my first when obummer decided to end import of russian guns. I went to the local gun shop to watch the panic buying. Comparing the russians with the chinese guns it was evident the chinese gun was of better quality. When i got it home i was eating up all the info i could find. Found i got a steal. Years later i spotted one just like it for same price and scooped it up. Iv thought about selling one for years but have not made any move in that direction. I have no idea how rare they are but i expect they are worth double what i paid. Maybe more.

Locally at gun shows i see regular mak90s with price tags of 700-800 on them. Havent seen many. Your market may be higher.

Having read some of your other posts (especially societal collapse) im curious as to the reason you bought one

I bought this because I used to have a similar Norinco but with a milled receiver. I bought it for $200, 25 years ago. A friend of mine really wanted one and kept begging me to sell it. I sold it to him for what I paid for it.  It was a good shooting gun. Kind of missed it since then.
This one came with 10 East German magazines and 3 mag pouches for them. The mags look brand new. I thought it was a decent price considering the mags. I seriously doubt these guns will get any cheaper but who knows. I may even sell it when the election hype starts later this year. Will see.  
Personally, I'd prefer my Colt M4 (LE6920) if fecal matter hits the fan. It's just a much better weapon platform. It's very accurate, reliable and easy to maintain.

Might i suggest you look into the vz58. Its not quite as good as the AR platform but i think its close or at least can be made close. Iv got a soft spot for 7.62x39. Its the best platform for the caliber in my opinion. Most will think its an AK though. Actually i bought the second mak90 thinking i could make a buck on it and buy a Czechpoint version but my century vz has not given me any issues at all and is damned accurate. Havent felt the need to upgrade and selling guns sucks. You always regret selling unless you bought a zip22. I did, never shot it, sold it at a loss but since i got rid of it is still consider it a win.

Do you have a slant cut receiver or straight? You can modify most surplus wood furniture to fit. If you want real expensive nice wood ironwood designs is always an option.

Apex gun parts is good for muzzle breaks, front sights, furniture, etc. If they have surplus bulgarian stuff that is GTG.

Good question. I'll try to remove the stock to find out.

"for a ugly Chinese AK clone? WTF ? the chicom AKS rank pretty high over most , in my opinion the pecking order would be Russian , Bulgy , then Chicom

Sorry - I have them all and the factory Hungarian guns (Kasner imports) are right up there with the Russian stuff.  Just sayin'

Chi com always goes bang though like most milspec AKs!

Point of interest: the inventors name is Kalashnikov, with a K. Therefore it's called a MAK-90, Modified AK 1990. This isn't Mcdonald's