Can't get a new engine from Cat???
Is this a gray market machine?
EPA certified versions of the 3066, 320B has been sold into US. As I recall, the certified and the non-certified versions weren't very different on the outside. Maybe different pistons bowl geometry and injectors and timing. I'm not entirely sure.
The local Cat dealer should help. This 320 class hex is a very popular selling machine. I 'm sure the dealer can help get rebuild parts, a direct replacement, or retrofit a certified engine.
Have you tried them yet?
Of course, I recommend following all federal and state EP laws. :thumbsup