pretty sure the pistons are different,realistically mate if this was a good or cost effective conversion it would have been done to death by now,i just wouldnt waste my time or money as there are other options out there that are tried and tested
at the end of the day you are going to need pistons and rods that will probably have to be custom made and cost a fortune,the sump and pick up pipe are at the wrong end as well on a sierra engine btw,so mods to sump or downpipe required,am sure people tried this years ago on turbo cars and the crank was weak as fook
power engineering stopped making their 1900 cvh as it was working out too expensive for their customers i read somewhere
if you want 1800cc so much go buy a zetec