Yes, I'm well aware of the existance of the O-240 powered F150's, though I have never had the opportunity to fly one, and don't know about the Mogas suitability of the O-240.
The IO-240 was worthy of consideration for STC'd installation into my 150, other than the requirement for the use of 100LL. To me, any benefit in the added power is lost in the need for the Avgas,