i put duel exhaust on my 67 conv., and it fits w/ two mufflers in the rear seat area. the driveshaft tunnel will accept the two pipes if time and effort is used w/ no problems. i ordered the original style hangers, and the factory hanger locations are perfect for the new pipes. my camaro has the 327, so a slightly smaller dia. pipe was used, but from what i saw as the job was done, there is room for the pipes. and the stiffener can be bolted on place,(that was the tricky part about fitting the pipes, so they would not rattle on the stiffener). there are several camaros in my area and they all have duels run like this
Regards, Strat