A process for manufacturing high octane gasoline from a low octane paraffinic naphtha, which comprises hydrocracking a first portion of the naphtha to yield a C4 fraction comprising isobutane and a hydrocracked light naphtha fraction having a relatively high octane number, catalytically cracking a second portion of the naphtha to yield a C3-C4 fraction comprising propylene, butylenes and isobutane and a catalytically cracked light naphtha fraction having a relatively high octane number, and reacting, in an alkylation zone the hydrocracked C4 fraction and the catalytically cracked C3-C4 fraction to yield a high octane gasoline alkylate. The proportion of naphtha charged to the hydrocracking zone and the catalytic cracking zone are adjusted such that isobutane, butylene and propylene charge to the alkylation zone are in stoichiometric balance.