K & N for HS6?

["A. B. Bonds" <ab@vuse.vanderbilt.edu>]

I am finishing up a redo of my MGB mill and would like to get K & N air 
cleaners for the HS6 (1 3/4") carbs.  Unfortunately, finding out the 
suitable part number is like pulling teeth.  I am looking for bolt-on air 
cleaner assemblies, not just the filter,  I have been able to find that 
they come in three heights (1 3/4. 2 1/2 and 3 1/4 inch), but cannot relate 
that to part numbers (no pictures on the various web sites).

Any clues/recommendations??

A. B. Bonds