i'm to young to know a whole lot about it but i know back in the 50's and 60's alot of farm tractors ran on propane, you can easily tell which ones were propane cause of the large round tank buldge out of the hood never knew anyone that had one but one year when i was doing FFA corn drive one farmers place we stopped at had a Minneapolis Moline LP tractor and me being one who is interested in old tractors/cars/trucks i looked real close at it (from a distance) and he had it setup with a fuel line that when to a LP tank that you would use for a house he just had the tractor parked on a cement slab and it was hooked up to a corn dryer (stationary use) i thought it was a pretty cool idea
Nate