I have a 354 cubic inch 5.0 / 302 motor in my Cobra. I'm doing research on header size "again". I used an auto math web site to calculate my header size. It says I need 1 3/8" for 354 ci at 6500 rpm. But I was reading a article on master motor builders and the Ford small blocks (347 - 360 ci) used 1 3/4" or 1 7/8" headers. I have 1 5/8" headers and I'm going to replace my Lone Star side pipes with a pair of Classic Cobrapack mufflers. But now I'm confused about the header size.
Does anyone have a link to a header calculator site or know what size headers I need with a 354 ci motor at 6000 - 6500 rpm?
I'm always looking for something to change
Dwight