If you could find an epoxy that would bond with the manifold it might be salvageable. First you would have to get the epoxy to work, then you would have to remachine the grooves and mill the surface flush with the rest of the manifold.
Another thing that might work is cutting out a section of a stock cmcv, milling out the frpp intake, and gluing in place with epoxy.
Both would require having a small machine shop or better yet a friend with a machine shop.