engine part numbers please

Hi all,i wonder if anyone can help me please.im in the middle of a part engine rebuild due to a blown head gasket and one cracked piston.

im after some part numbers, as the parts im replacing the numbers are different and i dont know which parts to buy.

the engine is a disco 200 tdi from a 1990 model the number on top of the piston is ERR1387 is this standard size?what is the part number to order a new one.

the con rod bearing shells are numbered up with ERC8841 are these standard size as well?

many thanks if any one can help me.
Martin.

they are std, but new pistons need to be measured properly to check correct fit with bore ,piston err1390 brg rtc2993

Ok thanks,apparently there is two std sizes X and Y mine has a X stamped on the crown so all sorted now just waiting for parts so I can crack on with it.

gap rings in bore before fitting pistons