Don Terrill’s Speed-Talk

bobmc wrote: ↑Tue Oct 08, 2019 6:51 am you see manifolds advertised as "permanent mold", what does that mean? and is it better than sand cast?

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.