I know this is a common problem but I can't seem to help this no matter what. When I bough my blazer it had stock exhaust manifolds with smog pump etc except no converter with pipes exiting between rear tire and bumper at a 90* angle. If any window was down I smelled like I had fell in the fuel tank. Since then I have changed the exit area 3 times and no help. I now have a TBI 350 with headers, 2 1/4" pipe and flowmaster 40's. Had them exiting behind rear wheel at a 90, at a 90 facing downward 20*, dumped downward just in front of rearend, and dumped just behind transfer. Even with back window rolled up if I let my drivers window down will be seeing double within 20 miles. Going to have a new exhaust system made this week or next to raise the exhaust out of harms way so please give me any input you have as to how to have the pipes exit as to help kill some fumes.