what does this sound like as a posibility?
silvertop 2.0l with black top pistons and rods, silvertop head.
as far as im aware black tops have dished pistons so that would lower the compression somewhat but im thinking it may not be enough.
the pistons are different heights but so are the conrods so the overall lenght is the same and the diameter is the same too i believe!
anyone heard of this?

 

thats a new one on me, why not just go forged pistons n steel rods also full "silver" or "black" top im not sure if that you can mate them 2gether

 

Pretty sure the black top pistons are flat top too.

They do have a different deck height which would drop them down the bore and ower CR if you mated them to the shorter silver top rods except thats not possible as they have different pin diameters.

 

yeah they have different pins.
i had some in the past and they where made by mahle with ford stamped on them with carbon bits front and back on the piston sides with a dished top.
they were said to be from a black top 2.0l std engine, they were dished!

 

Focus RS pistons have quite a substantial bowl in the piston!! Someone has some for sale on here, go check to compare....

But yes, no reason not to run them in a silver top block. The geometry is practically the same.