I managed to cram an evo 35 with rear mounted pitts muffler in a H-9 Mustang. Mount the engine rails, slide the engine back with the muffler attached, get out your moto-tool and remove whatever is in the way. Reinforce whatever areas you can and build a box of wood around the back of the muffler. Fuelproof everything when you are done. Go slowly and remember, it's hard to put the pieces back if you do it wrong.