Hi all

This recent talk of OS engines has lead me to try and clarify in my head the differences between the OS engine suffixes.

I own an OS 35FP ( in a stunter ) this engine is, I believe, made in the 1990's and is the all silver type.

I believe there is an OS 35FS also.

What are the differences ?

Also the later blue coloured ones come with various suffixes, is there a general rule one can follow to I.D. the spec of these ( such as all FS are ballraced or ABC etc etc ) ?

John in the N.W. UK