Which Vortec head?
Thread Starter
Drifting
Joined: Nov 2005
Posts: 1,361
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From: Downriver Mi.
Which Vortec head?
Hi to all,I'm trying to decide what casting number Vortec head to get,I have read that the 906 does not flow as well as the 062 casting,anyone know the skinny on that? 
looking at a pair on flea bay need to know soon Thanks Dave
looking at a pair on flea bay need to know soon Thanks Dave
Drifting
Joined: Jan 2005
Posts: 1,335
Likes: 310
From: San Antonio Tx
From the Sallee Chevrolet website:
"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 Sallee 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!!!!!!!! "
"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 Sallee 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!!!!!!!! "
Burning Brakes
Joined: Apr 2005
Posts: 1,110
Likes: 0
From: JUPITER FLORIDA
Yeah I have the castings that are made for trucks ( heavy duty valve seats are what the difference is).
I like the heads except the fact that they have a limeted lift for a cam. You have to machine the spring seats and the Valve guides so you can fit a bigger spring on there. I heard that beehive springs will do the trick and you wont have to machine the heads with those, but you still have pressed in rocker studs which are not as good as threaded. That is another thing that has to be machined if you want a monster lift. Max lift for my head is about .480. Cheap and good bang for your buck.
I like the heads except the fact that they have a limeted lift for a cam. You have to machine the spring seats and the Valve guides so you can fit a bigger spring on there. I heard that beehive springs will do the trick and you wont have to machine the heads with those, but you still have pressed in rocker studs which are not as good as threaded. That is another thing that has to be machined if you want a monster lift. Max lift for my head is about .480. Cheap and good bang for your buck.
