Ted, I forwarded an ad to your email. If you're not interested, maybe you can post it for others.

I contacted two members by text/email. Here's the find: There is a complete, rebuilt marine 312 for sale, by owner, for $900 on SF Bay Area Craigslist. If it runs as good as it looks, it would be a shame to disassemble it to part out. 

Jeffrey.  Internet and Email was down for several days due to the Arctic Freeze that rolled through my area.  Even now the internet service is spotty and I’m just now able to get on just long enough to post this.
 
You’re right on me not being interested due to shipping costs.  Shipping on my end pretty much does away with engines being cost effective when shipping prices are involved.  Also be aware of reverse rotation marine engines.  There were a good number of single engine boats equipped with a reverse rotation engine and that was simply to make it more cost effective to make the reverse rotation engines.  There were ultimately more reverse rotation engines made than dual engine bolts to put them all in.  Hence the use of them in single engine bolts.
 
Here’s the link to the marine engine in San Francisco.
https://sfbay.craigslist.org/eby/pts/d/emeryville-ford-block/7275457643.html

Lorena, Texas (South of Waco)