I have a Black racing series 850 CFM Proform Carburetor. We found a vacuum leak after installation and first run, noticed the area once our hand was placed by the carburetor. The second picture with the black circle shows the area of concern. It appears that this was dropped at some point which caused separation in the block at the purple and black meet. We went ahead and ordered a new one rather than trying to locate and find the purple replacement part. Everything showed is sold as a kit. There are multiple gaskets, seals, fittings, fuel pump. If someone has the time, it is worth it to put it back together.  The carburetor alone is worth $700, was only installed and started once.