Heavy gas oil components, coking process recycle, and heavier hydrocarbons in the delayed coking process are cracked in the coking vessel by injecting a catalytic additive into the vapors above the gas/liquid-solid interface in the coke drum during the coking cycle. The additive may comprise cracking catalyst(s) and quenching agent(s), alone or in combination with seeding agent(s), excess reactant(s), carrier fluid(s), or any combination thereof to modify reaction kinetics to preferentially crack these components. The quenching effect of the additive may be effectively used to condense the highest boiling point compounds of the traditional recycle onto the catalyst(s), thereby focusing the catalyst exposure to these target reactants. Exemplary embodiments of the present invention may also provide systems and methods to (1) reduce coke production, (2) reduce fuel gas production, and (3) increase liquids production.