The answer is #"9273 J/g"# of #"S"_8# are evolved in this reaction.
If you look at the balanced chemical equation
#S_(8(s)) + 8O_(2(g)) -> 8SO_(2(g))#
you'll notice that 1 mole of #"S"_8# produces 8 moles of #"SO"_2#, which explains why the heat of reation is #"-2374 kJ"#.
The heat of formation for 1 mole of #SO_2# is #"-296.81 kJ/mol"#. If you have 8 moles of #"SO"_2#, you'll get 8 times as much heat evolved for 1 mole of #"S"_8#. This means that the heat produced by 1 mole of #"S"_8# will be equal to
#"-296.81 kJ/mol" * ("8 moles SO"_2)/("1 mole S"_8) = "-2374 kJ/mol of S"_8#
As a result, the heat evolved per gram of #"S"_8# will be
#"-2374 kJ/mol" * ("1 mole S"_8)/("256 g") = "-9.273 kJ/g"# of #"S"_8#, which is equal to
#"-9273 J/g"# of #"S"_8#
