There are offerings from EZM and AGK. (Click the names for links to them)
The EZM will require drilling to fit the mount pattern of the HF79 which is easy to do.
I have read that they will do this for you before it leaves their warehouse if you ask, but I have no first hand experience with this. Take this info for what it is worth, hear-say that is worth researching further.
Another big thing that effects the drive system mounting is how you plan on mounting the engine.
Horizontally or vertically? Different bolt holes are required for vertical mounting and is a drill them your self situation.