The Stanley Blower has an oval "horn/mouth" (with adjustable angle) that the air exits through. As I recall, it was about 10" by 4". The only modification I made (if you can call it that) was to creat an adaptor between the 10" by 4" blower exit and the 8" ducting I used.
All I did was take a sheet of fairly thin, flexible, plastic and wrapped it around both pieces. I trimmed the plastic, to the right shape as I went along. Then I tied it up real good with string to hold it in place. When I was happy with the way it looked, I drilled a few small holes where the plastic overlapped. Then I took the whole thing apart, added some glue in the appropriate places and re-assembled the thing using small nuts and bolts in the previousely mentioned holes.
When the adaptor was finished, it was held in place with good old Duct Tape.