OS 46 AX in a heli?

[Chrisk7]

Can anyone tell me why not to put an OS 46 AX airplane engine in an EVO 50?
Can a guy just get a heli head for it for better cooling?
I already have a like new OS 46AX engine and was just wondering.
Does anyone know if the 46 or 50 heli heads will fit the AX series engines?

Thanks again for any input.