I'm modifying a JET DC100, I am doing the same conversion as TimmyG. I have all of it done, but I am trying to fugure out how far the outlet pipe from the DC barrel should be inserted to the top plate, The other Question is that the inlet to the DC barrel is 5" and the inlet to the DC impeller is 6". What I'm asking is will the larger dia. make a diffenrence in air speed, I have been unsuccesfull in my iposting on this site. So I am asking for some help??????