Here are the exhaust stubs for the HuaSheng:
The flanges are 1/4" thick, and the tube is 7/8" OD x 3/4" ID.  1.5 inches long.
A good place to start if you want to use a flex pipe or build your own exhaust system.
Price is $15.00 plus shipping  I ship USPS flat rate, and will ship as...