Still a newbie .. could use some help and advice..1971 Sierra 2500

[ItzhakRoberto]

So i've got a 1971 GMC Sierra 2500
I'm trying to figure out what size engine I have... this is my first American vehicle and I haven't ever really looked into it before so i've got no knowledge on this. I bought this truck off a coworker who had got it into an accident, and i already collected all the body parts but now i need some help with mechanical/engine parts. There are some things that got damaged, being the radiator, ac condenser, water pump, crank pulley, fan, fan clutch and that pulley, water pump......maybe the steering...
But what i need help is figuring out what engine size i have.
I don't want to buy parts for the wrong engine.
I don't have any pics right now ...hope someone can guide me in the right direction
Thank you

[geezer#99]

Without a pic, who knows!!
If it's a small block or big block,
Look here for casting locations and how to decipher them.
http://www.mortec.com/

And look here for suffix codes.
http://www.nastyz28.com/decode.php

[everettelane]

I was just looking it up looks like the sierra didn't come out till 72, but i'm no expert if you look in the glove box you will find the vin code and you can decipher it but i think all it will tell you is v8 or 6 cylinder etc. but it could be 307,350,402 for that year. the 402 would be a big block hope this helps.

[68shortwide]

If you want to email me some pics at 68shortwide@gmail.com I'd be glad to try and help and even upload the pics for you. If you could get a pic behind the drivers side valve cover on the main block before the bellhousing of the transmission where the numbers are it would narrow down what it is.