You have seen the on off my 350. It was made out of SS because early on when we were getting it figure out it would sometimes sneeze hard enough to crack the aulm one. This same thing would happen on the turbo scimitar in the early days when Cliff had it as well. I know there are some mathmatical formulas that some guys are using to size the plenums, but on the bikes, its damn near dictated by the size constraints of the chassis. I used OEM airbox boots to connect the plenum to the carbs, but obviosly they were OEM carbs. All of these that I have been around do have a baffle in the box that keeps the turbo from just blasting the back of the carb inlet. As for the BOV, its just gotta be on there somewhere.