A method of preparing high linear paraffin or high end-chain monomethyl content products is accomplished by converting synthesis gas in a Fischer-Tropsch reaction to hydrocarbon products. These may be hydrotreated to provide an n-paraffin content of greater than 50% by weight, with substantially all branched paraffins being monomethyl end-chain branched paraffins. At least one non-linear paraffin isomer, which may be a monomethyl paraffin isomer, may be separated from the hydrocarbon products through distillation to provide an n-paraffin product having an n-paraffin content percentage by weight of the n-paraffin product that is greater than the initial n-paraffin content.