I'm not entirely sure that graphic and the 2500 examples thing is correct.
Location : As original.
Position : Free.
Orientation : Free, but the engine must remain
longitudinal (or transverse) if originally
longitudinal (or transverse).
Local modifications are permitted for :
– the replacement and/or the moving of the engine supports
– the addition of mountings for new engine supports
Location I believe is defined as the centre lines of the car. So as long as it's still behind that, it can be freely positioned. BMW and Corvette would have to move the engine behind the centre line, so that wouldn't be allowed.
I used to have a good link explaining this but can't find it now.
Edit: Page 9 -
https://www.fia.com/file/51741/downl...token=Y5vP01g2