O-ring type. Most seem to stick with the stock size, a 428.
This is what I went with:
Get the rear wheel up in the air, break the master link (a good pair of pliers works well), hook the new chain to the old one with the master and pull it around the front sprocket.
You may need a chain press to install the new master link (or be good with a vice grip and a small nut) remember the open part of the clip faces away from chain direction.
For longest life change sprockets at the same time, but sounds like for you that would be a dealer job.