Discovery 2 4.0 v8 changing to 3.9 v8

My Discovery 2 4.0 v8 suffered a slipped liner.. rather than go down th costly route of rebuilding that with replacement liners i sourced a 3.9 v8 which i rebuilt and am considering putting the D2..
However, how the hell do i get round the crank sensor problem? i cant use the distributor as i dont have the wiring for it. im debating on grafting a hole in the block where the 4.0L crank sensor sits.. ive had worse problems to overcome, but i really need to know if there is an easier route..

I presume that you are only thinking of fitting the short engine from the 3.9