What is Chevy motor 395511?

There's no publicly available, comprehensive database of all Chevrolet engine serial numbers and their corresponding specifications. The number 395511 is far too short to be a complete engine serial number. Chevrolet engine numbers usually contain many more digits and letters.

To identify what this number refers to, you'd need to provide more context. Where did you find this number? Is there any other identifying information associated with it, such as a casting number, a vehicle identification number (VIN), or the engine's location (e.g., block, cylinder head)? With more information, it might be possible to determine what it represents.