Wow, I rarely see a vintage machine in the shops around my place. You are blessed. Singer 301 and 401 are great. The 401 has zigzag if that is important to you. The 301 is a straight stitch only but easy to change bobbin, service yourself, weighs about 16 pounds so great for taking to classes.
Click on the link below, it will take you to the Vintage Sewing Machine Shop on this site and put you on its last page. There are hundreds of pages you can glean from for all the info you could want about machines. Careful though, it can be addictive!
http://www.quiltingboard.com/vintage-antique-machine-enthusiasts-f22/vintage-sewing-machine-shop-come-sit-spell-t43881-892.html