how can you tell the difference between the stage1's and stage2's or even the stage 3's???
i tried the search but its not working

 

Well the lobes should be quite a bit bigger whenever you are looking at the different stages.

If you are buying them from someone then you might call skunk 2 and find out the specs on the stage you think that you are buying and them measure the cam to see if the lobes match up to the specs.