Complex sentence: Porsche's 914/6 variant came with a carburated 2.0 L flat-6 engine from the 1969 911T, placed amidships ahead of a version of the 1969 911's "901" gearbox set up for mid-engine operation.
Split into simpler sentences: Porsche's 914/6 variant came with a carbureted 2.0 L flat-6 engine, taken from the 1969 911T. The engine was placed amidships, in front of a version of the 1969 911's "901" gearbox set up for mid-engine operation.