What headers for 440 A body

I've been searching threads and haven't found a clear answer on what headers will actually fit. For every thread that says one set fits, there's another that says it wont. I'm trying to find a set that will fit my 74 duster with a 440 and a 4 speed OD. What size tubes will be best for performance? The car currently has a 3" exhaust that dumps in front of the rear wheels. Will this system work for the 440 when I get it in? If not bigger or smaller? Any advise is appreciated.