Farmall designed their tractors back in the 40's to be dual burn. I think it was due to the was and available of gas and kerosene. You started it up on gas, got it hot, and then switched it over to gas. My grandfather's H was designed that way. He ordered it in the 40's. Our newer M model had a higher compression engine and used only gas. I always thought that was a very unique solution to a war time problem IH was trying to address.
My dad told me he and my grandfather had a WWII era H that had maybe a 1 gallon tank for gasoline and a larger tank for kerosene. Would start tractor on gas and and then switch over to kerosene using a petcock plumbed into both tanks. He was told this was done to conserve gasoline for the war effort. Tractor was traded off in early 50's before I was born. Sure wish he and my grandpa would have kept it