I have just used the Asoociation parts lists to try and get my head round identifying some old parts. I thought conrods would be easy, but the countless parts catalogues don't seem to give me anything for 1A 348 connecting rods from anything old through to 3 bearing Rubies.

Can anyone tell me what they are for? They are all whitemetalled and one set of 4 has extra stamped 4 digit numbers (presumably to match the set)

thanks