While
@RonD might consider swapping 2.3 for 4.0 a labour of love; I consider it a great learning experience for a neophite. You learn all about pulling transmission, pulling engine, wiring, rerouting intake & exhaust with something you can always look at what the factory did. And maybe you do the 4.0 SOHC from a slightly newer Ranger/Explorer into your '97 for almost as much power as a V-8/less weight/better gas economy.
Then once you have skills/tools, branching out to something factory never sold. I hate to see projects listed as started but were too ambitous so never finished.
Even the 302 will require some minor cutting of the HVAC.
302 is recommended as it was found in Explorers - which were bascally Ranger SUVs at the time. So, a lot of the same
year generation Explorer just transfers into the Ranger. It still not just drop and drive, but there are few enough issues (and most of those are well documented) that your chances of success are good.
351W has some minor issues with the steering (and a little more issue with the HVAC).
Any other engine requires more work - wiring, intake, exhaust, etc. (not something you want to do for your 1st swap).