A 3.7 in a KJ is probably ok, but a ZJ is a a little big for the 4.0. I have one with the 4.0 and a 249 transfer case and it is SLOW. If you're ok with slowing down and taking in the sights, then a 4.0 might be ok for you. But I would look for one with a V8 if I was going to buy another ZJ...