I designed the 3D model for Ohmite C40-058-AE for a project. I searched it all over the internet but couldn't find it. You can download it here, the archive contains only Inventor parts and assemblies of the heatsink and associated clip for TO-247 package.

It's also available at 3D ContentCentral if you want it in other formats (SW, step, etc), just search for "Ohmite C40" and you will get to it.