Catalytic cracking process

A process for thermally and catalytically upgrading a heavy feed in a single riser reactor FCC unit is disclosed. A heavy feed is cracked in the base of the riser at higher than normal cracking temperatures for at least 1.0 seconds of vapor residence time, then quenched. Quenching with large amounts of quench, preferably downstream of the mid point of the riser, increases conversion as compared to use of the same amount of quench within one second. Small amounts of quench, near the riser outlet, crack heavy feed roughly as well as large amounts of quench, near the base of the riser. High velocity, atomizing quench nozzles reduce riser pressure and/or catalyst slip in downstream portions of the riser, further increasing gasoline selectivity and reducing coke yields.