I'm looking for the 80's black/thrash sound (Venom, Bulldozer, Bathory), or the oldschool south-american black metal sound (Sarcofago, Holocausto, Vulcano), so it could be helpful if you name a few.

The ones I already know are:
Bathory, Tormentor, Bulldozer, Venom, Sarcofago, Holocausto, Vulcano, Exterminator, Mystifier, Hellhammer, Celtic Frost, NME, Beherit, Blasphemy, Death Yell, Maniac Butcher, Master's Hammer

Hey Varoth, how about Masters Hammer ?

You should look into Sextrash. Filthy black metal in the old South American vein.

What about recent bands that sound old school???

@Almighty Ent: Forgot to add them to the post, will edit it now.
@Mecha Zombie: I've heard one SexTrash song and it was good. I just need to find some more. What release of them would you recommend to try first?
@Mother-Anorexia: Those would be ok, but I would prefer old bands better...

Ive only heard Sexual Carnage, but I would definitley recommend it. I think you may already know them but also listen to Sabbat and Abigail (both from Japan).

You can try Anal Vomit too

there's a band from my own country called Hetroertzen, they're awesome... I would say my favourite South American Black Metal band... they play very hypnotic, dense music and extremely atmospheric, with the old-school attitude... I specially like their album "A Crimson Terrible Vision"... they also released one of my favourite BM albums last year: "Rex Averno", which is much more filthy and extreme than their previous works.

Thanks for the recommendations, I'm gonna look for Sextrash, Anal Vomit and Hetroertzen.

@Damnated: I know Xasthur, and they aren't really oldschool.
@Ace: There's no american Nocturnal (but you told me on Msn that you meant the german one), and the german Nocturnal is more of a thrash band, IMO (I know them already, they are quite good). Thanks, nonetheless.
@Puff: That joke is older than internet itself o_o

If you wnat old school BM try magog from Sweden , but its more Viking metal, but great and Estonian band Bestia and Lithaien - Luctus., alsdo latvian and Nightwing, all aer in MA and home pages are mp3m

Aura Noir would fit the category. they aren't so old but the sound is totally thrash/black.

Have you ever heard Vinterthrone from Macedonia?
There are few mp3s on http://www.soundclick.com/vinterthrone
Or the official blog, http://vinterthrone.blogspot.com

Speaking of Macedonian BM bands, check out Maras and Tremula. I think on the p2p the split with Vinterthrone/Maras/Tremula can be found.

apart from whats been said already: early 'order from chaos'

Can we have Besatt listed here?

@varot
well I know 2 great bands, but you menation them , but ist ok
Thank''s to you I discover Maniac Butcher and thank's to ozman i discovere Masters Hammer and those bands w aht you menation in first post are great too
maniac Butcher lil but remaind me early Immortal Great band

You should check out the compilation cd Fenriz released. It's full of bands like this, you can get it here

http://shopping.theendrecords.com/s.nl/it.A/id.8672/.f?sc=2&category=2061

Check out Extermination.

You shood try Aura Noir its old school black/thrash metal and fast i same time like venom
http://www.auranoir.com/
There are 2 sonsg from each album

Ammit from Chile, Goat Semen and Black Angel From Peru... very filthy, uderdeveloped Black Metal pledging allegiance to the old school

You all shood try this band
http://www.vibrationsofdoom.com/test/Hobbs.html
Its old school thrash/speed/black simmilar like Bulldozer

I jsut take this from MA
'' Hobbs' Angel Of Death is one of the most important bands in the history of Australian metal. The band started out in 1986 as a solo project of the band leader Peter Hobbs. The band played thrash metal in the Slayer vein but Hobbs himself referred to their style as "virgin metal" as he saw it as an untainted and pure form of metal. Their self-titled debut album was released in 1988 through Steamhammer Records. The band dissolved soon after the release but seven years later the band reformed to release their second album called "Inheritance" which was basically only distributed in Australia. A long period of silence followed until the band reformed once again in 2002. In July 2003 they signed a four album deal with the native label Modern Invasion Music.
Before 1985 Peter fronted a band called Tyrus (Aus). In 1986 they released one demo and a promo live single tape .''

PS
If this coppy material from MA are dunno forbiden I will remove it, just PM me

Try Nifelheim

Varoth: I'd be surprised if any one can add things of use. I can recommend some newer bands, I actually thought one was old but it wasn't, which is the band "Dishammer", Neutron Hammer is pretty damn good too.

I think you'd enjoy old Samael, old Impaled Nazarene, Filii Nigrantium Infernalium, old Deathspell Omega, and Odelegger. Ildjarn's Son of the Northstar EP is something I have a hunch you'd really like. If you've heard it already, reinvestigate it. I actually think it's quite underrated among his releases, and definitely has a crusty, old-school vibe.