Welcome to the forum

Ford, GM, Buick, Chrysler all made a 3.8l engine

Ford used a 3.8l up to 1997 in the T-bird, but only 150HP, super coupes used supercharger for 200HP but need extra room for that

Work required to do an engine swap, to a different displacement, will be the same regardless of the engine, some just won't fit, too wide
Fords 5.0l(302) V8 engine was just 19" wide, so fit into a Rangers engine bay, tight but fit.
They were 210HP stock, but loads of upgrades for these, very very popular engine.

So look up the dimensions of the engine you want to use to see if it will even fit inside the Rangers engine bay, as said 19-20" width would be about it, you will have to move steering shaft and heater box if you go over that

For a swap you need the engine, of course, lol, the transmission for that engine, computer and wiring harness.
Ranger transmissions are engine specific, even for other "Ranger engines" can't swap them

Exhaust and drive line, probably radiator as well