if you have a non abs 240 than the drive shafts will be around 3/4 inch too short...now people have just bolted them up and had no problems, and a couple who have had trouble with the smoothness of it; personnaly i don't want to run the risk. I like to do things right the first time and not worry about braking stuff. people do use the non abs shafts, it's personal preference on risk really.
Also whether you knew or not
j30 vlsd has 3.916 ratio
240 has 4.083 ratio
if that matters to you or not

