3000W Chinese Gensets Info.

Have the Power Pro from Pep Boys. Had a fellow who makes aluminum boats make a box to go over it that is attached to a carry all that goes into a 2"receiver hitch. The box is made of 1/8" aluminum diamond plate with the front and top hinged. Bottom of box is open over the expanded metal floor of the carry all. Just couldnt think of leaving the generator out in the rain on the rear of the fifth wheel for 1000 miles at a time. Cost was $400, only $100 more than I paid for the generator. I hoped it would reduce the noise more. There is some reduction when the top is open, but not as much as I had wanted. Dont know if I will try to put something in to deaden the sound more or not. MY QUESTION: Where can I find something to fasten to the exhaust (7/8" outside diameter) to route the exhaust out of the box? I need to get the heat outside. Any suggestions gratefully accepted. Al in VA.