755.rar -

: Lists of components, such as rocker box covers or internal engine "pieces" that cover specific assemblies of the 755-series radial engines.

Based on the technical context of the query, it is likely that "piece covering 755" refers to a specific manual or part related to the (or Lycoming R-755) radial engine. 755.rar

: Archive files containing technical drawings or installation steps for aviation or industrial lighting systems (e.g., "Installation manual of R series light.rar"). : Lists of components, such as rocker box