WTB - Vortec heads, 062 castings
#3
Le Mans Master
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Member Since: May 2002
Location: Lebanon Township New Jersey
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I don't claim to be an expert but I've read alot lately and it seems that the original type Vortec heads came in 2 types, 062 and 906 castings. The consensus, from my research anyway, is that the 906 is less desirable because of some hardened exhaust seats which can't be machined. I should know which type I am using now, so I will pull a valve cover to check the number. I bought mine originally from Jegs.
#4
I found it:
Please Note: The casting number myth debunked:
The myth is that there is a difference in the head performance produced by these two castings.
This myth was started by some Magazines that didn't do their homework before publishing their articles.
This is the truth the whole truth and nothing but the truth. So sayith the Grand Wizard GM and his Apprentice Wizard Chevrolet.
10239906 casting has one large single hump.
12558062 casting has 3 small humps.
If either of these two castings have not been altered by GM and the part number changed from 12558060 or altered by someone else (previous owner, etc.), the heads produced by either casting will be identical except for the external cosmetic difference. Both castings are used to make the 12558060 Vortec heads which are the true unaltered Vortec heads.
Heads from both castings come out of their cast IDENTICAL except for the minor cosmetic external differences!!!!!!!!
Please Note: The casting number myth debunked:
The myth is that there is a difference in the head performance produced by these two castings.
This myth was started by some Magazines that didn't do their homework before publishing their articles.
This is the truth the whole truth and nothing but the truth. So sayith the Grand Wizard GM and his Apprentice Wizard Chevrolet.
10239906 casting has one large single hump.
12558062 casting has 3 small humps.
If either of these two castings have not been altered by GM and the part number changed from 12558060 or altered by someone else (previous owner, etc.), the heads produced by either casting will be identical except for the external cosmetic difference. Both castings are used to make the 12558060 Vortec heads which are the true unaltered Vortec heads.
Heads from both castings come out of their cast IDENTICAL except for the minor cosmetic external differences!!!!!!!!
#6
Melting Slicks
Just to add to the casting myth.....I put one of each casting on the bench and proceeded to do my own lowtech reasearch. I measured everything from here to China on those heads, and everything was the same....within a C-hair or two. Mix and match at your disgression...That will screw everyone up that has a look at your heads
I have a couple of sets.....but I don't think you want to pay shipping from Alberta, Canada....
I have a couple of sets.....but I don't think you want to pay shipping from Alberta, Canada....
#7
No, I am not selling a pair. I do use vortec heads in my '73 though. I just figured that I would help to increase your odds of finding a set by not limiting them to just one particular casting.
#8
I found it:
Please Note: The casting number myth debunked:
The myth is that there is a difference in the head performance produced by these two castings.
This myth was started by some Magazines that didn't do their homework before publishing their articles.
This is the truth the whole truth and nothing but the truth. So sayith the Grand Wizard GM and his Apprentice Wizard Chevrolet.
10239906 casting has one large single hump.
12558062 casting has 3 small humps.
If either of these two castings have not been altered by GM and the part number changed from 12558060 or altered by someone else (previous owner, etc.), the heads produced by either casting will be identical except for the external cosmetic difference. Both castings are used to make the 12558060 Vortec heads which are the true unaltered Vortec heads.
Heads from both castings come out of their cast IDENTICAL except for the minor cosmetic external differences!!!!!!!!
Please Note: The casting number myth debunked:
The myth is that there is a difference in the head performance produced by these two castings.
This myth was started by some Magazines that didn't do their homework before publishing their articles.
This is the truth the whole truth and nothing but the truth. So sayith the Grand Wizard GM and his Apprentice Wizard Chevrolet.
10239906 casting has one large single hump.
12558062 casting has 3 small humps.
If either of these two castings have not been altered by GM and the part number changed from 12558060 or altered by someone else (previous owner, etc.), the heads produced by either casting will be identical except for the external cosmetic difference. Both castings are used to make the 12558060 Vortec heads which are the true unaltered Vortec heads.
Heads from both castings come out of their cast IDENTICAL except for the minor cosmetic external differences!!!!!!!!
I've done a couple small block Vortec head projects and either the -062 or -906 head casting number will work just fine.
As mentioned, this false rumor started a few years ago by a nationally published car magazine doing a Vortec head article at the time that contained some very false info.
The magazine quickly corrected the bad info in a later issue.