I think the engine mount holes are there, just not necessarily tapped so you'll need to address that.

The dipstick holes are also in different locations, but that's relatively easy to sort out too - block one up, drill another in the right place. Job jobbed.

After that you just need an appropriate sump for your application to clear any crossmember or wot-not.

Other than that, I believe the FWD and RWD engine block castings are the same. There was one guy over on RS2000-16v.net who was putting a scorpio 2.3 block in his RS but haven't been over in a while to see if he got it finished or not.