RysiuM,
I believe that it is designed to meet California emmissions. I seen a post here where the guy blocked off the aux port with a custom manifold and used a standard carb setup. Just check the duration of the main intake port. The duration should be between 110 and 145 degrees. The 2 barrel Toro trimmer engine has a simular intake system. The secondary system is just blocked off and a standard carb used.

Dave