OK I have this find and I hope that you can help me figure out what I have here.

Someone here will give you more specific info. I will try the basics. The 3970010 is a 350 c.i. block from the 1969-1980 era. I believe there was one year of the Z28 302 c.i. that carried the same casting number. If I remember correctly, the K04 05 is the month and day of casting and the CGC indicates the application, in this case is  a full size sedan, truck, or El Camino. Stand by for the experts!

Scott

It's an L65, 245hp 350, 2-barrel engine from a '71 Nova or Chevelle.  As long as it's in good shape...no block cracks, etc., there's no reason it can't be used as a good base block for a build-up.  I'd still have it checked by a competent shop to make sure it's solid internally.

As with all built engines, I would always recommend using ARP bolts to reassemble it with.  It may or may not use 4-bolt main bearing caps, and if not, ARP bolts will do the job nicely.