I've heard of "Factory Propane," but there's some debate locally as to whether or not trucks actually came propane equipped from the factory.
Does anyone here know for sure?

 

The F150/250/350 series trucks did not come with factory propane that I am aware of. Perhaps there was an obscure fleet option but for the masses, I've never seen one.

The larger F & B series trucks did come with a LPG option.

 

I've seen trucks and cars from Canada with propane installed. Whether it was factory or not, I have no idea. I know right where one is, an 80's crown Vic with propane on its sbf. I live in northern Montana BTW.

 

They used the 7.0L engine in the 1993-1996 F & B trucks with the Duraspark II ignition system. They also used a pick-up coil inside the distributor and not a PIP sensor.

 

I drive a bus, it's a 2015 F550 V10 with LPG conversion. 4mpg, and not totally impressed with the power. It's not terrible, but not great, either. Rumor was the conversion cost $10k

FWIW, the bus body is Glaval, and we've had terrible luck with the A/C on the bus body.