The invention relates to a method for processing asphaltene-containing feed to a pyrolysis furnace by raising the final boiling point of the feed/steam mixture to the pyrolysis furnace to ensure fouling occurs lower in the convection section where the mixture of air and steam can burn off fouling deposits during decoking operations. The final boiling point of the feed stream is increased by adding a heavy essentially asphaltene-free high boiling point hydrocarbon to the feed stream before the feed stream enters the convection section of the pyrolysis furnace, whereby said fouling occurs lower in the convection section.