Downpipe moding idea...question(s)?

[electryc_monk]

/delurking mode
I have an idea for using the belly space better. First the vehicluar facts: 99 F350 SC LB 4X2 SRW auto I'm wanting to take the time to Mcgyver/modify a 4 inch downpipe at the tranny crossmember - which BTW happens to also be at the rear of the I-beam on the pass side.... the mod is to have possibly 2 90 degree sections of 4" pipe to sneak the exhaust right behind the I-beams rear mounting bushing *hinge* location (whatever its correct nomenclature is). Then take all the heatshielding and unbolt it from the inside of the pass frame rail and swap it to the outside of the frame rail. Now, after the double 90 degree stuff run 4 or 5 inch pipe back to just in front of the rear tire and drop out nice clean and smooth looking. This will allow the install of a second fuel tank where the current exhaust is sitting and bang-pow-zap ballance fuel weight, more usable bed space, up-fitted exhaust, modestly lower CG (potentially)....
Now for a tangential question: anyone know how to go about finding the names or part numbers of the exhaust gaskets that go between the headers and turbo and turbo down too? I admittedly now know I NEED to fix some exhaust leakage. (might as well do it at the same time as this downpipe moding... I remember thread that was on some forum about the first step was supposedly remove/lift the cab - does this ring any bells folks? <br>
here's the link (i hope it works) to see a basic picture i just made with "paint.exe" and realized that I still need to install some software to scale down the image.... sorry bout its size folks...
route for the exhaust to take - TheDieselStop.Com Photo Hosting

/resume lurker mode for now...