Hello. i just purchased 2 350s, 1 appears to be a 75 block with #8 heads, but i have not been able to find any help decoding the other 1. (3A11744789 with 3A heads) can anyone help? Which block would be the best candidate for rebuild?
Thank you

 

I'd pick the first one.

The second one you mentioned is a 77-79 350.

 

Thank you