Couldn't say definitely myself as never seen the floor pan but I guess it's the same for most commodores etc. Fuel filler & tank position stops being able to run the second outlet past the rear wheels.
Common way around it is a fuel cell in the boot, delete the fuel filler.
What about side mount exhausts that exit in front of the rear wheels? Don't really know to be honest. I think the exhaust has to exit past the cabin opening by a certain amount doesn't it? Which might give enough distance between back of door opening & rear wheel being a monaro.
Custom Fuel tank & altered filler to fill from the rear like a Torana & run dual exhausts out the back? Would mean your fuel tank would be reduced in volume unless ran a custom drop tank. (This has been an idea I've been toying with but not for a Monaro. For my older VK Calais which will have a LPG tank in the boot & gas injection, if I do it. Not something I could imagine doing to a Monaro though)
All of the above mentioned may be irrelevant & not useful at all, I can't say but sure someone has some other idea's or can correct me by saying just can't be done or just do this etc.
Anything is possible if you throw enough money at it :thumbsup::air: