The GX50/35 are weed whacker motors and only mount from the clutch side, not from the bottom. Ideally for inframe you need a HS144f, 142f, 79cc predator, my opinion. Those are the engines most used as 4 stroke inframe mounts. Anything is possible with the right install. Just need to decide what you want. 79cc is a sweet 3hp motor, lots of threads here for guidance.