Do You Own Big Block MP Valve Covers?? Please Read This ... and Share

But are they CRACKS, or do they start as stress risers that crack from handling/installation/sandblasting/the phases of the moon?


No, it's most likely caused by lack of maintaining the dies. If you do not keep the dies clean and the gates start to get restricted, then they do not fill completely. If you do not fill completely, you get a "short shot" which doesn't allow the material to "pack" properly before cooling and you get hairline cracks and/or porosity in your metal.


Tooling maintenance is something that companies often take shortcuts on to save costs.