I'm pretty sure those H/F 212cc Predator engines are manufactured by Loncin and are a slightly more modern version based off the LC170F model.
The air cleaner, gas tank and recoil are shaped a little different on the H/F model, but if its any help you'll find some measured LC170f drawings at this link:
http://www.lanticmotor.com/download/Loncin GPE Products Catalogue 2009.pdf
Harbor Freight really should include some measured drawings on their sites ads so they dont loose potential customers like you. You could probably email/call them and get the overall height and width measurements if you explained your situation...
The newer style 208cc Maxx 208, Ironhorse or Powerhorse engines sold at Northern tool are made by a different manufacturer, but you'll find measured drawings to those here at this site:
http://www.lctusa.com/