ive been looking around at the local yards for a lq4.
but how can i id it as a 6.0l lq4,

 

anyone know how to confirm that its a 6.0

 

The block has "6.0L" cast into the front driver's side of the block near where the water pump attaches (there's also a "6.0L" cast into the back of the block, that's the one in my avatar)... Here's a pic:

I ran some yellow chalk over the casting to make it stand out more. I don't know if that part of the block will be readily viewable with the engine in the truck and the accessories attached... I can't remember if they put the displacement on the engine beauty covers... If the intake cover says "Vortec 6000" then it is a 6.0L. Also, I think the heads on a 6.0L are a different casting than those on a 5.3/4.8L, however, I am not positive. Here is a pic of the casting # on my 6.0L head passenger side, front (also located on driver's side, rear):

Hope that helps! Good luck

 

Also if your lucky and the truck still has the emission's sticker on the factory airbox, that will tell you all that you need to know. If not then you will have to look for casting numbers as posted above. Good luck man, im doing this swap too, can't wait to have that Gen III power!