CastingNumbers.info was launched on December 18, 2010. It aims to be the single biggest online database of casting numbers, OEM part numbers, GM RPO codes, and more.
Casting numbers can be found on all sorts of auto parts, from engine blocks to axle housings. Often times, these numbers are one of the only accurate ways to determine what a part actually is. For example, all Small Block Chevy engines look nearly identical on the outside, but can have significant internal differences. The casting numbers found on the block can narrow down what the engine really is, and in some cases, when or where it was made.