Welcome to the Part Trace database project. The goal of this website is to create the largest searchable database of casting numbers, engine codes as well as other various bits of automotive information. No longer must you spend countless hours scouring the web searching from site to site, only to find bits and pieces of what you are looking for. We have compiled over 4,000 casting numbers, over 4,000 GM RPO codes as well as several thousand GM engine codes. Other manufacturers are to follow.