RS500 block is different and easily identified by it's smaller core plugs, compared with 205/200 blocks.
The main difference with 4wd 205 blocks as fitted to all 4wd sierra/escort cossie is thicker webbing and material especially around the area of the gearbox end.
If assembled right a 205 will take 450 all day long.
RS 500 blocks can further be identified by the ridiculous money they command.
tabetha