When I asked Napa, here in Canada they said no, although there is enough demand out there for them.
They might be wrong but I haven't found any on Google.ca either
there isnt enough back pressure with a 4.3 to need a true dual exhaust... run a single in dual out muffler comming from a high flow cat, excellent preformence and sound
there is no power gain, and all hurt from running a true duel on a six cylender moter. like i said, for the duel look, single in 2 out, magnaflow catalitic converter