I think where the lbf measurements came from were different sources From the Pratt Whitney F135 article I can already see that the stats come to 178 kN for the engine while the High Performance engine the General Electric Rolls Royce F136 is also 178 kN for the entire system There is a minor change in lbf but I am not sure these are accurate I do nt know why the secondary engine is labelled High Performance anyway if I can t find credible sources then I will remove this Yes I know I m not signed in but I am The1exile