5 1/4" long
6" Diameter (at widest point)
76mm neck, comes with reducers
1 1/2" pipe to attach to reduces
4" (pipe + reducers)
According to james at iconstyling.com
Should fit quite nicely into my 820 airbox!
EDIT: One extremely high tech test later:
http://desto.net/pub/airbox_sizes_test.gif
Looks like it will for sure!
Andrew