Is there a way to change the property names that are not user data?

Example:  In the project properties I'd like to use the "Contract number" field because it can be filtered in the project manager.  The problem is, I want it to be called "Machine Type" for example.

Is this possible?  I thought I read somewhere you can, but every time you update your custom fields will be overwritten which may be fine depending on how difficult it is to change.

Thanks,

Zac