For what its worth, my two cents says go with a 235 I-6. They are cheap to aquire, very inexpensive to maintain and you can still "rod" it out if you want and have something that most likely no one else in town will have anything even close to.
Unless you plan on driving hours and hours at a time on the open highway, a good old 235 fixed up right should last you a very long time. I say, save the V8 for your "other" project!
The most important thing is have fun and enjoy your old truck!
