I’m new to the forum but I’m currently building my 67 mustang with a 302 from a mountaineer with trickflow 190cc 56cc 11r heads, f303 cam, scorpion 1.6 rockers, 1 5/8 headers but I’m debating on which exhaust set up to run as far as piping size. Can anyone help? I’m stuck between 3” or 2.5”. Will be running both 91 pump gas and e85. Not sure if this is the right place to post so sorry if it’s not.