Hi I don't know about re conning , but series motors can have 200 or300td from a disco fitted but also require the gear box axels and wiring and some modes done to fit it all in, but it is possible there is folk here which I'm sure will pop on and give you more information, if you end up getting rid is said engine give me a shout as just fitted a 2.5 n/a diesel to mine and struggling to get it started and yours may have parts to help fix mine so please shout me if your getting rid of it.
On anther not there is other engines that fit the original 2:25 petrol and diesel but I suspect one engine mount on drivers side would have to be change back for it to be fitted and is basically a start swap bar connecting up its start stop which is easy enough done.
Hope this helps
John