Looks like it's a New Vertical Feed (NVF) from the link below.
http://www.kelsew.info/domestic/davisVFmodels.html
I would go to
http://www.quiltingboard.com/vintage...ll-t43881.html
and ask questions there. There are a few members who have and love this machine!
P.S. Did you notice it doesn't have any feed dogs? It's fascinating!