when ever i had a bad motor i just bought a new one. the 3.3s are even more cheaper now than a few years ago. i seen one on ebay for 85 bucks. brand new. no kidding. you got to use yr own starter, carb, etc.
even if you do rebuild. you still got to break it in. so i always went new. my 2 cent.
You could buy a new engine, though at some point you'll have to learn how to rebuild. It's up to you. However, the piston and sleeve need to be replaced. While you are in there you may as well replace the bearings too.