Hey, I "sort-of" asked this question in an earlier post, but I decided that I should probably break down my multiple-question post into seperate topics.

But what I need to know is the above question, what is the piping diameter for the collector on a JDM Header? I remember seeing it in a huge h22a header comparison post online a few months back, but I can't seem to find the post anywhere...

Any help will be appreciated, I keep searching but I can't find a definitive answer. I think it's 2.25", but I haven't found anything to verify/refute this and I would rather not wait until the motor arrives on Wednesday to order my cat.