I've been doing some research regarding the legalities of building a hood stack for my '92 D350. Seems Idaho law says its ok, so long as the exhaust gases exit above the cab. An ISP who pulled me over for going too fast(me...going too fast? Who da thunk it ROFL) said he did not know of any law prohibiting a hood stack in Idaho. His concern was mainly visual obstruction. So, with those thoughts in mind, I'm working on a hood stack for my rig. I'll post pics as I make progress.