On a manifold it would be a "semi permanent mold" the exterior would be formed by an iron mold, but the interior is still formed by a sand core.
An iron mold is better when done properly.
Some of Edelbrocks high production heads are semi permanent.
I don't know of any US cast manifolds that are done in permanent tooling.
The industry is in steep decline right now, no none is going to pour money into that.