I believe all heads later than the original 5.7 and 6.1 SRT8 heads are side specific. Why....no clue. I know the head gaskets for the 6.4 are side specific.
Looking at my bare cnc ported Eagle heads I dont see a difference. I will look closer tonight.
Look at the oil drain locations in the head that go to the block. I believe that is why there are left and right sides.
The exhaust flanges are side specific as well as the oil drainbacks. They can all be converted to universal though.
