For what it is worth I have spoken to a couple different folks about getting custom headers for a RB A-body....both said when the tubes get bigger they normally run a couple of them thru the fender....
I have a custom set of marco headers for an a-body bigblock. They were in a 440 duster. The front tube on each side goes straight down, instead of over 2nd and 3rd, and two pipes on each side exit through the fenderwell.
They are 2 3/8 tubes, and a four inch collector. The question for a 440 is..... why? (Maybe right for a 900hp 540" B1.....)
