I have a 1976 f-150 4x4 with a 428 on propane since '88.

The propane guy is ok and I have bought parts from him he is just slow at responding sometimes, better to phone him.

I live in BC and it sounds like propane is a little more popular since gas is around $400 a gallon or 95c /litre.

can try to answer any questions

go single fuel only
pick an enigne with a long stroke (300six /fe block)
excellent cooling system

was worth it when propane was cheap but not anymore