I beg to differ Dr Hunt, but that IS a Rover V8 (same as a Buick 215). Look closely:
If it now displaces 5.3L, that's an accomplishment. It must use some pretty long stroke crank for that. In fact, if you cut down the mains on a Buick 350 crank (3.85") and drop it into a Rover 4.6L block with a 3.7" bore, you get 5.3L (331 CID). Nonetheless, that is a rover aluminum block.
Greg