There is a new adapter available to install a Rotax C gearbox on a Phazer engine. Phazer C-Box Adapter – BK Experimental Made in America. The adapter allows the gearbox to be installed up or down. The owner is flying a Kolb Firestar 2 with the prototype gearbox adapter, C box and Phazer engine. He likes it!
The adapter may also work with a Rotax E box but you should verify that before you try it.
The adapter may also work with a Rotax E box but you should verify that before you try it.