Fischer-Tropsch synthol naptha is upgraded to high octane gasoline with minimum yield loss in a multistep process comprising fractionating the synthol naptha to give a C.sub.5 + C.sub.6 fraction and C.sub.7.sup.+ fraction, processing the C.sub.5 + C.sub.6 fraction over a ZSM-5 catalyst under dense phase conditions, pretreating and reforming the C.sub.7.sup.+ fraction under conventional conditions, and blending the C.sub.5.sup.+ products from both the C.sub.5 + C.sub.6 and C.sub.7.sup.+ processing steps.