Well seeing my engine will be producing close twice the stock HP (600HP/550TQ) I'll need a min of 3" pipe with an X-pipe. I'm gonna run CATs as well, so the less restriction, the better. I don't really want a fuel cell. I like the idea of the truck looking as stock as possible. All my mods after the big block swap will be to making it look stock with a little lift.
The header collectors are just outside of the frame, by the cab mount. So I will add my cats there and then either go inside the frame and down the passenger side, or run pipe straight down the outside and go in to the spare tire location where I will have the 2 magnaflows mounted. The 2 pipes will dump stright out the back.
In my province it's illegal to have pipes dumping infront of the back tires unless it came like that.
The problem with running them straight down the frame rails is adding an X-pipe.... If I run them inside the frame on the passenger side I can make the X-pipe easy, but putting CATS on will be hard.