Let the ride decide wrote:
This might be helpful for your research,http://www.ebay.com/itm/1954-PACKARD-AIR-CONDITIONING-SERVICEMANS-SHOP-SERVICE-REPAIR-MANUAL-OCT-1953-/311798545256?hash=item4898a43b68:g:CU8AAOSwjDZYm70c&vxp=mtr[/quote]

The service training book has good photos and print so worth having for that alone. It also has a few pages on theory and description of individual components that is not in the 51-4 service manual. The rest of the book consists of the same service and troubleshooting info that is in the AC section of the service manual.