If you are thinking about this header set but are ambiguous because you don't know what the size of of the y-pipe primaries are, here is your answer. Since my caliper won't reach past the sockets where they will cup the headers I can not get an ID measurement. I would not be surprised if they measured 2.25. However, the y-pipe collector does measure 3 inches.

Owner caption February 2017 · Photo 38 of 107