New Project but No Experience
To add reliable power a 5.9 Magnum will do the trick. They are plentiful and reasonably priced. You can keep fuel injection but you'll need a high pressure fuel pump. I used a carburetor on my swap and kept the v-belts to keep it looking old school.
I haven't done a V6-V8 swap so I'm not sure what all is involved. Like mentioned above, the search function works great for finding info. But feel free to post if you need more info or clarification. For a V8 swap, I would definitely swap out the v6 torsion bars for larger ones such as 1.03".
And...welcome to FABO!! Glad to have you on board.