I do not know how to read the number you have provided. I believe it is a VIN derivitive number providing a matching number (or not) to the engine.

I believe the info you need is on the ID tag attached by the factory to the transmission. It will have a number like 68 CA 375 and should look like this:

http://corvetteforum.net/c3/1970registry/04102_th400tag.jpg

If it came out of a chevy, this should help.
http://www.novaresource.org/trans.htm


"Nothing astonishes men so much as common sense and plain dealing." - Ralph Waldo Emerson