Originally Posted by justdirtr/c
the guy that it is working on it told me he drained the oil that it seemed to have a lot of oil in it.
Something that came to mind when I read that part that the mech may have forgotten - the 4.0 uses 6+ quarts of oil, whereas the majority of engines out there use less than 5. Look at any coupon for an oil change, it usually says "up to 5 qt." I say 6+ for the 4.0 because if you run an oversize oil filter like many of us do it will hold between 6 and 7 qts to the top mark on the dipstick.
If you do need a new engine, I would focus on 2000 or 2001. The distributorless ignition system was introuduced in 2000 so prior engines may need some extra modification and/or a different PCM to be complatible.