Difference 205 blocks

[twin turbo]

Is IT some difference in early and late 205 blocks (not rs500) just normal and 2wd cossie?

I have heard something about difference in bearings, but never looked more info IT... I have a couple blocks, and some oversice cossy parts i will trow into IT as a low spec budget engine to put in a 4x4 wich will only have greens and t34.