Minecraft / Set Block. Block to the north, etc?

I'm currently building a map for my friend and I wanted to know if / how you can use the / setblock command to make blocks look in one direction? I'll explain the situation. I have given a block a texture and want to replace it with another block via the command block, but when I do that the new block looks backwards and not forwards.

To do this, you have to try it out a bit, just enter:

/ setblock (your coordinates) (your block) (and here you just try numbers from 1 to 4)

When you find the right number, the block should look ahead.

Wow that was easier than i thought thank you.