David:

**I know the new and rebuilt 550's in Legacys run pretty well LOP -- even
without GAMI injectors.

Do the rebuilt 540's do this also???  Or do you need GAMI injectors to
run them LOP?**

The 540s are not as well balanced without GAMIjectors as the 550G.  As a matter of fact, some of them are a real bear to balance.


**Do 540's run just as efficiently LOP (ie same SFC) as 550's???**


The TIO-540 and TSIO-550 have very nearly the same CR.  They have very nearly the same BSFC(min), so the answer is "yes, they're pretty close in efficiency."

Walter