could also run the drivers side like was routed from the factor but have dual pipes down the passenger side. You can then run a dual in dual out muffler like the dynomax 17553 to keep space to a minimal. I had a friends do that on a chevy 1500 and it came out good with out interfering with anything
1971 F100 sport special 390 fe
1993 F250 4X4 ext-cab 6.9 idi
My stock 71 CS 390 option has factory dual exhaust , it has the original hangers and hanger locations. If you want I can get some pictures of the front pipe routing as after the aux fuel tank its pretty straight forward.
I think the cross member might be unique to dual exhaust but you might have to see if your is the same and go from there.
Let me know if you want some photos.