I just looked it up in my textbook though, and it says: "The heat released on combustion of a substance is called its heat of combustion. The heat of combustion is equal to - :delta: H° for the reaction written in the direction shown."
I know that for enthalpy, like you said, if it is exothermic, then it is negative. But then wouldn't it be the opposite for heat of combustion, and if it is exothermic, then it is positive? Sorry I'm just kind of confused as to why some sources seem to have them both as keeping the same exact sign while the textbook says they should be different signs - is there one that's more correct or something?