I am  using the ford v8 not the rover , has the same install  problems though. I have made up a flywheel using a diesel  mitzi shogun ring gear <12" diameter> That takes a tvr twin plate clutch. Engine has a back plate with the mitzi reduction gear starter, that just leaves me to make or modify the getrag 265 bellhousing.or buy one of these 
http://t2.gstatic.com/images?q=tbn:A...ggQeyYo8wzX6Dw  All this allows the lump to go back without altering the gear tunnel. Also the top of the cylinder heads are only  40mm above the top side rail of the chassis, there is also loads of room for the headers and steering column.Cant see the rover being much different other then its about 4" taller. Here is a v8 locost   
http://www.youtube.com/watch?v=ZhNUG3t3NRU and something scary 
http://www.youtube.com/watch?v=GqCnMahHGbk
Bob