You need a copy of the original manuals published by Helm to inform GM's employees how to build, repair and service the cars. Chevrolet issued a Service
manual to all of the line mechanics to repair anything that wears (brakes, shocks, front end) or explaining how to rebuild the power train (motor tranny and rear end). The technicians in the body shop that had to repair collision damage by welding on new sheet metal, painting and adding back trim pieces used the Fisher Body Repair
manual. On the assembly line workers who where new, or when there was a major body change refereed to the yearly Assembly
manual that explained how to install every part onto the car. Speaking of parts, though they are no longer available from Chevrolet seeing a picture and knowing which parts where used where can be found in a copy of the 1954-'75 Illustrated Parts
These books appear occasionally on line as original greased stained copies printed on paper, but it is easier and cheaper to buy a copy of them that have been computer scanned and burned on a CD for $20 each (except the parts manual that is usually $75). You can buy a copy of these manuals from the original publisher Helm at:
or from others who have licensed a copy from GM (these books are still copy righted and should not be published on line without permission from GM).
I have been collecting rare bound printer original books of all of my favorite cars and trucks from various years that I own so that I can work on them without any surprises. They generally run from $65 to $145 per book whenever I find them at auction on e-Bay or Craig's List.