Nothing better than an OEM manual for the engine and drive. Doral does put together a good owners manual. When we had our 270, the manual had wiring, plumbing and dash diagrams. There are a couple of 310 owners here but when I went to look it up in the Doral forum here, it seems to have disappeared.
Google Boatmax in Midland Ontario. They used to be our local Doral dealer. Shoot them an email. You never know what they may have sitting around.