the only good thing about the rover is its light and efi would be the only one worth havinga jeep v8 bolts right in with factory parts and gives all the power you can need and yes the tranny will stand it no probs
if you use a Early range rover 727 box change the output shaft and rear housing from the 999 [tf6]you can use the range rover bell housing adapter
almost no diff in the weight power output are net hp so look weak and as for thirst dont bet on it
RR 3 speed auto is a Chrysler [tf8 ]
the rover v8 is a nice engine for flatfenders