I recently bought a set of focus rs pistons for doing my zetec turbo conversion on a low mileage silver top, I am told you can't fit them to the standard zetec rods and wondered if this is true or whether it is possible to convert the rods to run with these pistons.

 

The rods on the black top are 3mm longer and the gudgeon pin is slightly smaller in diameter being 20.00mm as opposed to the 20.63mm (?).