3" exhaust with a ford 9"? (HELP)

I have a 73 duster and need to know if anyone has used a ford 9" rear and been able to squeeze 3" pipes up over the rear, stock location on springs. Options .. 1. fuel cell? 2. reduce pipe size though I really don't want too... 416 with 650HP 3. dump in front of rear? Anyone running fuel cells and car smelling like gas? I'm just not really sure what to do here....????