Is there a set standard as to what defines a "stage 2" vs. a "stage 3" head? I used to think it was just different valves, however, I see some manufacturers using the same size valves in their stage 3 heads, as others use in their stage 2's. I am doing a head/cam/header package on my 2002 M6 and don't know whether to go with the stage 2 or stage 3. I am keeping a stock bottom end for now and the near future, so does that make a difference in what I should choose? Will I see any additional gains with a stage 3 head since I'm keeping a stock bottom end? Thanks.

 

There is not set standard for stages on heads. The porters/manufacturers label them to fit their own needs. Some people's stage 2 are the same as other's stage 3 heads.

 

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