461 head question
Thread Starter
Le Mans Master
Joined: Mar 2005
Posts: 7,631
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From: Rocklin California
461 head question
I have a set of 461 heads for a 65 327. One head has a casting GM 9, the other GM 7. One dated 6-12-65 and the other 6-17-65. Any idea why the different GM number?
Thanks
Thanks
Thread Starter
Le Mans Master
Joined: Mar 2005
Posts: 7,631
Likes: 11
From: Rocklin California
Le Mans Master
Joined: Feb 2006
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From: "cutesy" TN
Thousands, two plants, big blocks, small blocks, six cylinders, four cylinders, plus all the other cast stuff.
If a part came to inspection, (after it cooled down enough to touch) and it did not pass they could track it down it fix it (just a guess).
Race Director
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From: Mustang OK
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If you go look at MANY GM castings, you will most likely see the GMXX mold number on them (somewhere). Imagine if you will, if there was only ONE mold for a block, one mold for a head, one mold for a rearend casting, etc, etc, etc. It would take FOREVER to turn out block, head, intake manifolds, etc. Sooooooooooooooooooooooo, there are multiple molds for the raw castings.
Next, why does each mold have a number, ie GM1, GM2, GM14, etc? Well, you touched on it. When a number is put on a mold, it provides a level of quality control by allowing inspectors to go straight to the mold which a cast part came out of, if a problem is discovered with that casting. Then the mold can either be corrected or discarded. Molds for cast iron castings are sand molds, so if an imperfection is discovered, the mold can ususlly be "fixed".
Such a thing may exist, but I have never seen a set of dies for die casting iron. Metals such as alum is usually where die casting is done. A good example between a die and sand cast alum part would be a carb housing is die cast and an intake manifold is sand cast.
Hope this helps.
Next, why does each mold have a number, ie GM1, GM2, GM14, etc? Well, you touched on it. When a number is put on a mold, it provides a level of quality control by allowing inspectors to go straight to the mold which a cast part came out of, if a problem is discovered with that casting. Then the mold can either be corrected or discarded. Molds for cast iron castings are sand molds, so if an imperfection is discovered, the mold can ususlly be "fixed".
Such a thing may exist, but I have never seen a set of dies for die casting iron. Metals such as alum is usually where die casting is done. A good example between a die and sand cast alum part would be a carb housing is die cast and an intake manifold is sand cast.
Hope this helps.
Team Owner
Joined: Oct 2000
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From: Washington Michigan
The patterns were usually made from iron or stainless steel, and there were up to 30 identical patterns for a high-volume casting; when the green sand was packed around the pattern, the sand became the 2-piece "mold" after the pattern was removed, and the sand "mold" was destroyed when the mold and casting hit the "shake-out" table after the casting cooled.
See my technical article in the February '07 issue of "Corvette Enthusiast" magazine for a complete photo-illustrated description of the Chevrolet iron foundry processes.
