Cummins Tech Section
Page 94, full view pre-cleaner.
Warning, PDF is 30mb
http://www.donaldson.com/en/engine/support/datalibrary/061238.pdf
There are two 3" models, one supplies 170 CFM, the HD one is 320, but bigger in size, since this is a cowl intake the smaller would fit better between the windshield and hood...