An internal combustion engine has a channel member such as a plenum chamber or cylinder head or the like with an inlet receiving air and fuel to form an air-fuel mixture and with a pair of outlets furnishing the air-fuel mixture to respective cylinders or groups of cylinders or to respective cylinder intake valve openings of two-intake engine cylinders or the like. A heating device mounted on the channel member has a heat-exchange surface which intercepts the air and fuel from the inlet to heat and fully vaporize the fuel to form the air-fuel mixture and also to divide the fuel mixture between the two outlets for furnishing the fuel mixture to the individual cylinders, groups of cylinders or intake valve openings.