As far as I know 4.2 litre Nissans are no longer available so you have no other choice than to buy a 3 litre. Hopefully yours will be reliable but they have a really bad reputation for dying a very expensive death and are called Nissan handgrenades. I would swap a few oil leaks and the occasional electrical problem any day for the knowledge that my motor will most likely not blow up for no reason other than apparently poor design. 120,000 - 140,000 seems to be the danger period for those motors. If you get past that then most likely you have a good one.
Ian

