I would do that if it were feasible with regards to supply in my area. I live in the boondocks and the closest place that sells propane is a good little drive away. The gas station is down the street.

I used to date a girl whose parents owned a bottle gas company. They sold everything from acetylene to nitrous for both medical and non medical use. They had a early 90s model chevy that had converted to propane. I believe it would run off gas and propane with just the flip of a switch but mostly they ran it off propane because they got it wholesale. It had over 300k miles on it and developed a leak around the intake gasket. I helped her brother replace it and when we opened the motor up it looked like a brand new engine on the inside. I am sure the cylinder walls had the standard ridge on them and stuff but as far as carbon build up and sludge from oil it was cherry. I was very impressed with that. I have not seen them in about 10 years but I do see them driving that truck around town from time to time. I dont know if the engine has been replaced or rebuilt since I worked on it but if not it has to have close to 500k on it by now and it still seems to run strong.