Thread: Vortec Heads

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Hi All,
Is there a way to visually identify Vortec heads? I just bought a car with a SBC of unknown heritage. It has 4 top valve cover hold-down bolts, as opposed to the more traditional side hold-downs. Also, does anyone know of a good site to translate the block number to it's original configuration? Thanks.

The four valve cover hold downs you mention, plus the intake manifold has 8 bolts holding it down, as opposed to 12 on non-vortecs. (4 bolts per side on the top of the intake.)


Don

Thanks for the info. When was the Vortec setup first used?

Vortec heads were used only on turcks and starting in 1996. It is confusing because the word "Vortec" is a Chevy engine name like the "Blue Flame" and "Turbo Fire" engines of old. The engines for years immediately prior to 96 were also called Vortec but were not the high flow heads and central point injection that we know as Vortec. The LS style motors replaced the Vortec stuff in 2000 or 2001 depending upon the model of truck.

Here is a link to info on the heads:

http://www.sallee-chevrolet.com/frame.html?/start.html

mike in tucson

Mike: I'm not a Chevy guy normally, although I am using one in the T. It is a marine 350. a 1999. The heads are vortec, does that mean only trucks and marine engines used vortecs? My last boat had a 4.3 in it, and had vortec heads too.

So are these marine heads the vortecs that Chevy guys like? Just curious.


Don

If the heads are "Vortec", they have four manifold bolts on each side and the bolts are vertical (not at an angle like normal Chevy manifold bolts). The bolts are something like 6mm dia and torque to 12 ft lbs as I remember.
The two common Vortec casting numbers are:
10239906 casting has one large single hump.
12558062 casting has 3 small humps.

I forgot about marine engines, they could be Vortec also since the marine stuff is kin to the truck stuff. Yes, Vortec heads did not ship installed in cars. And yes, there are six cyl 4.3 Vortec stuff too.

If you look at the web page that I posted a link to, it compares the flow of the Vortec heads to several aftermarket brands....the "lowly" Vortecs match up really well and actually outperform the Edelbrocks and World Products heads at higher valve lifts. Note that Vortec heads when stock cannot accommodate cam lifts over about 0.450" (at the valve); they can be modified easily to go higher.

For iron heads on the street, they are really good.

mike in tucson

That all makes sense. I know all of Volvo's and Mercruiser engines have been Vortec since '99 in boats, I guess to take advantage of the increased HP. The one I am using is a Volvo 280 HP 5.7, and came out of a boat we repowered for a customer. I think the cam profile will be ok (it's a roller cam engine) and I hope by adding an aluminum intake it will bump up to maybe 300 HP.

Thanks for the good info.


Don

The 86-95 heads had centerbolt valve covers and vertical intake bolts like the Vortecs, this is not a good way to identify them.

All true Vortec heads have 3 triangles in a sawtooth pattern on the ends of the head. A head with a single large hump is not a Vortec, it is a high swirl head from 86-95 and is not desirable for performance. Both the 906 and the 062 heads have the 3 triangle sawtooth.

76GMC has a picture of a Vortec head.....note the four vertical bolts on each head and the bolt size...like I said, if it has the small bolts that are vertical, it is a Vortec. There is also a new GMPP Vortec casting that is dual drilled for the old style manifold bolt pattern and the new style pattern.

From the Sallee Chevrolet page:

QUOTE: "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 GILBERT 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!!!!!!!! " END QUOTE