I just found out my cossie block has YBS stamped on it, and not YBB as it's a 2wd engine.
The only info i found about it is they where 1990 spec group A engine blocks?

But if it's 1990 spec, why is it a 205 block?, you would think they would only use 200 block for group A by then?

Also, in what way do these blocks differ from normal 205 blocks?