I would advise heading to the local bookstore and picking up some books on the subjects. HPBooks publishes several, including "How to Rebuild Your Small Block Chevy", "How to Hotrod Small Block Chevys", and "The Chevrolet Small Block Interchange Manual". I believe the interchange manual focuses mainly on '68-up large journal engines, so the first two would be more helpful to you. I know there are dozens of other books out there on the subject as well, since (I believe) the SBC enjoyed the longest production run of any engine design!