Re: 1977 Silverton Manual
Odds are you aren't going to find one anywhere for a 32 year old boat. You can watch ebay, but it's a long shot.
The real question is why you want one. Boat manuals are usually not all that informative. If you have questions about your boat, the kind folks here will be happy to answer them.
If you have questions about your engine, you can get them here, too, and manuals for engines are available.
So, ask away.