engine case interchangeability
 

I have a 2.7 engine with a 7R case that I need to replace with aluminum one white at the rebuilding process, is it possible to retain all the internal parts but use a 3.0 or 3.2 case instead? do I need to replace the pistons/cylinders with case as well?

To be honest, I havent looked at it closely yet, its smoking a little bit on start up and got the usual amount of oil drips. I just don't like to spend a whole lot of money on a magnesium case anyway, so why not do the same job but on a better, aluminum case.

is the cylinder fitment the only issue here?

A replacement aluminum case for the 2.4/2.7 cases would be more stable, but a properly prepared magnesium case can be a good base for a great engine. Folks forget that the 3.0 liter engines now are old enough that they also need a fair amount of work, and are equally expensive to update for additional performance.