IF you go the 4.0L engine, best to use the A4LD tranny that's with the 4.0 engine. Explorer A4ld trannys were built better for the HP and torque of the bigger engine.

BUT they still have the same problem areas like front seal leaks and the OD unit gernading. Also you will need all fuel lines and tank for the EFI system. Best bet is finding a wrecked explorer and get the whole vehicle and start swapping over whats needed. Its all bolt in from any 91 to 94 Explorer.

For a 302 swap, that is more involved and not easy for someone who is just getting their feet wet. The 4.0L swap will be a good learning experance.

Now for me(after getting heckled again that it can't be done) I'm going to install a big 300 I6 from a truck in my B2. Now thats going to be a learning curve stuffing a LONG engine in there!