Finished cylinder assembly to case by installation of two remaining cylinders assemblies. Installed and torqued oil pan to case. Found slight surface corrosion (see attached) but non-pitting in new piston pin assembly for #3 Cylinder. This was packed in a sealed and corrosion inhibiting package new from Superior Air parts which part is in compliance with Lycoming Service Bulletin SB501B/527C and Service Instruction 1340A.