Where to start - maintenance on a 340

Removing the delay box is pretty straightforward. The ignition box will be a little harder depending on what distributor it’s running. If you want to remove it you may have to convert back to a factory type electronic ignition or points setup. If the ignition box is working I’d leave it alone. Oh and 10 years isn’t really that long. I wouldn't pull it all apart just yet. Get it running, tune it up and it could be just fine as far as leaks go.