Re: 2.3 to 4.0 swap questions ('03 2.3L)
the trans will need to be changed. the bell housing will not bolt up to a 4.0.
here is a basic list of stuff you will need.
rear axle wouldn't be a bad idea
your best option is to get a donor truck and sit them side by side and start pulling parts. if your truck has torsion bars, a v8 from an explorer will pretty much bolt in place as well, but if you have control arms/coil springs, then it won't.
Krylon Fusion is for Amateurs.