Hey Dennis;
It sounds like your 216 is a prime candidate for a rebuild. A lot of the guys, and gals, here might disagree that the babbits are not worth redoing. From what I've read here, there are still a lot of shops out there that can do it. If you keep the 216 cool, oil changed regularly, and keep the revs down, they'll go a long long time.
Just a suggestion, but before you throw a belly-button 350/350 in there, you might make a few phone calls around to the engine builders in your area and see what's available to you. There's a lot of 216's (fresh ones, too) still running out there.
