It is possible, but because of the torque arm on the rear end, it is very difficult.
Save yourself some headaches and run a single 3" exhaust system with a good perfomance muffler like a Flowmaster. 3" single will give you good performance and sound pretty decent, without the exxtra expense and complications.
I had and 82 firebird(orignally had the 2.8 v6) well i dropped in a pontiac 400(nothin fancy it was stock with stock manifolds) well to make a long story short my exhaust was a total headache i attempted true duals but due to ground clearance(even after i beefed up the suspension) i was constantly rippin my pipes off. All I can do is suggest a nice aftermarket 3" single exhaust or maybe have a good exhaust shop attempt the duals but that wont be cheap