A method of enhancing the conversion of a major proportion of a paraffinic naphtha feedstream into lighter hydrocarbon reaction products that include a high proportion of the lower olefins ethylene, propylene and butylenes, and gasoline, the method comprising: a. introducing a feedstream containing a minimum of 40% by weight of paraffinic naphtha boiling in the range of from 30°C (86°F) to 200°C (392°F), or a feedstream containing a minimum of 60% by weight of combined paraffinic naphtha and naphthenic compounds into the top of a first downflow reactor and mixing it with catalyst; b. operating the first downflow reactor with a residence time of 0.1 seconds to 5 seconds of the mixture of the feedstream and catalyst in a reaction zone at an operating temperature in the range of 480°C (896°F) to 700°C (1292°F) and with a catalyst-to-feedstream ratio in the range of from 25:1 to 80:1 by weight to produce a first reaction product stream that includes the lower olefins ethylene, propylene and butylenes, and gasoline; c. separating the first reaction product stream produced in the first downflow reactor from spent catalyst in a first stripper zone downstream of the first reaction zone; d. recovering the first reaction product stream from the first stripper zone; e. directing at least a portion of the gasoline contained in the first reaction product stream into a second downflow reactor; f. operating the second downflow reactor with a residence time of 0.1 seconds to 5 seconds of the mixture of the feedstream and catalyst in a second reaction zone at an operating temperature in the range of 480°C (896°F) to 700°C (1292°F) and with a catalyst-to-feedstream ratio in the range of from 25:1 to 80:1 by weight to produce a second reaction product stream that includes the lower olefins ethylene, propylene and butylenes, and gasoline; g. separating the second reaction product stream produced in the second downflow reactor from spent catalyst in a second stripper zone downstream of the second reaction zone; h. passing spent catalyst from the first and second stripper zones to a dedicated regeneration vessel for regeneration with a supplemental source of heat to increase the temperature in the regeneration vessel, the regeneration vessel receiving spent catalyst only from the first and second stripper zones and in which the quantity of coke formed on the spent catalyst is insufficient to raise the temperature of the regenerated catalyst exiting the regeneration vessel to the operating temperature range of from 660°C to 815°C,; and i. recycling the hot regenerated catalyst to the top of the first downflow reactor and the top of the second downflow reactor. a. introducing a feedstream containing a minimum of 40% by weight of paraffinic naphtha boiling in the range of from 30°C (86°F) to 200°C (392°F), or a feedstream containing a minimum of 60% by weight of combined paraffinic naphtha and naphthenic compounds into the top of a first downflow reactor and mixing it with catalyst; b. operating the first downflow reactor with a residence time of 0.1 seconds to 5 seconds of the mixture of the feedstream and catalyst in a reaction zone at an operating temperature in the range of 480°C (896°F) to 700°C (1292°F) and with a catalyst-to-feedstream ratio in the range of from 25:1 to 80:1 by weight to produce a first reaction product stream that includes the lower olefins ethylene, propylene and butylenes, and gasoline; c. separating the first reaction product stream produced in the first downflow reactor from spent catalyst in a first stripper zone downstream of the first reaction zone; d. recovering the first reaction product stream from the first stripper zone; e. directing at least a portion of the gasoline contained in the first reaction product stream into a second downflow reactor; f. operating the second downflow reactor with a residence time of 0.1 seconds to 5 seconds of the mixture of the feedstream and catalyst in a second reaction zone at an operating temperature in the range of 480°C (896°F) to 700°C (1292°F) and with a catalyst-to-feedstream ratio in the range of from 25:1 to 80:1 by weight to produce a second reaction product stream that includes the lower olefins ethylene, propylene and butylenes, and gasoline; g. separating the second reaction product stream produced in the second downflow reactor from spent catalyst in a second stripper zone downstream of the second reaction zone; h. passing spent catalyst from the first and second stripper zones to a dedicated regeneration vessel for regeneration with a supplemental source of heat to increase the temperature in the regeneration vessel, the regeneration vessel receiving spent catalyst only from the first and second stripper zones and in which the quantity of coke formed on the spent catalyst is insufficient to raise the temperature of the regenerated catalyst exiting the regeneration vessel to the operating temperature range of from 660°C to 815°C,; and i. recycling the hot regenerated catalyst to the top of the first downflow reactor and the top of the second downflow reactor.