Block Numbers??

I just bought a 65 Nova and the guy threw in a chevy small block. I checked the vlock and it had these numbers
3849852
Any ideas on what it is?

its a 283ci 1957-1966

here is the site with all the casting numbers....
http://www.mortec.com/

Is this motor worth building?

That part number might be a replacement number for a 1957 283, but the original '57 block would not have motor mount bolt holes on the side of the block. They mounted on the front of the engine.