Can I swap my 3.9 v6 in my 97 ram 1500 with a v8?
Not easily. Your engine now has six fuel injectors and plug wires. The V8 will need eight fuel injectors and plug wires. This means the engine wiring harness and the computer will need to replaced for the V8 engine. Plus who knows what else.
Tester
If you have unlimited funds, yes. It won’t be easy, however, because so many things will have to be changed along with the engine, like computers, wiring harnesses, etc.
And then there’s no guarantee it will all work together.
It would probably be less expensive to trade your truck for a truck with a V-8.
You need to find someone that has done this or put some time into thinking about doing it. The most likely place to find that info is on a board specific to Dodge PUs. It might be easier than some think or it might not be worthwhile considering. It is probably only worthwhile considering if you can find a donor truck that has been totaled, but the engine compartment spared. You need to get all the stuff inexpensively and install them yourself for this to be a reasonable exercise. Oh, there is no sense in starting this with a perfectly good truck unless you like to throw money into the wind. The 3.9 has to be shot too.