Anyone on Propane?

Thinking about a propane mixer for a motor. One of those common carbs that looks like a carb hat with a gas inlet. Anyone run one or have knowledge of them from a forklift? Saw the hot bench pic of all the Chrysler motors getting run in on propane(?) and it intrigued me for a test stand running a wideband so as to get the A/F right off the bat.