A while ago I got a set of aftermarket Vortec heads with the 86down intake bolt pattern on them. No Vortec bolt pattern. I didn't realize at the time that the intake ports on a vortec head are raised compared to previous SBC head ports. So now I have these heads with a pre-Vortec intake bolt pattern but with Vortec intake height intake ports. (I read in someone's post that the vortec ports are raised perhaps .300")

Does anyone know of any intake manifolds that may be able to accommodate this? Perhaps a manifold with rather large ports may be helpful?(Which I assume would cause issues aswell.)

Oh FYI - So no one has to chime in on it: Yes, the Vortec heads with pre-87 bolt holes were a big mistake. It seems like a good concept but apparently no one thought it through! The price was good, but that hasn't been helping me..

 

If they don't have the Vortec bolt pattern, they're probably not Vortec.

Cars are built using a process called "mass production". You may have heard of it. It's becoming popular; someday I expect nearly all complex consumer goods, even cars, will be made that way. The principle is, you make A WHOLE BUNCH of all the little piece parts that's all EXACTLY THE SAME; and that way, you can pick up ANY ONE of the various parts from out of its bin, and it fits to ANY ONE of all the other parts selected at random, without having to be "custom" "matched". That means, they're all the same size, same material, were made on the same machines, had the same processes applied to them, and ABOVE ALL, .... the bolt holes are ALWAYS in the same place.

Therefore if they don't have the Vortec bolt pattern, they're probably not Vortec.

Post the casting #. No point in confounding the confusion further until that's straightened out.

 

Hi there - sorry but they are aftermarket heads - if they were stock heads then the intake ports would indeed match the bolt pattern. However, some aftermatket Vortec chamber/runner/port heads are sold with an option for vortec bolt pattern, conventional bolt pattern, or both. The ones I purchased do indeed have the Vortec port location though they were optioned with the conventional intake bolt pattern instead of the vortec style.

So, I have the aformentioned problem of a set of aftermarket Vortec heads from EngineQuest/ProTopLine model CH350E that have a conventional intake manifold bolt pattern. This makes for a bad situation since the Vortec-style intake ports are raised vs the conventional location.

 

That would have been good info to include in the original post.

2 choices:

1. Get the right bolt pattern drilled into them, so you can use an intake that actually at least covers the ports; or

2. Find the "greater fool" (yes, in my long experience with humans, the one thing I've found to be dependable about them, the only thing maybe, is that there is ALWAYS a "greater fool") and sell them; and turn the cash into something more ... sensible.

 

Only option is a aftermarket raised runner intake ( usually race spec single 4bbl Hi rise style ) or welding and porting on a reg intake

FWIW;
many sellers promote the " dual bolt" pattern Vortec heads you mention without mentioning the limited supply of GEN 1 intakes that will fit correctly

 

Well, gasket makers such as Felpro sell gaskets with the combination that I am using - ie: Vortec ports with the conventional bolt pattern, also, other head makers give the option for the conventional bolt pattern on Vortec heads. So I'm guessing there are likely to be some intake manifolds available for the combo since some people do purchase it other than myself.

 

As I stated above;
the existence of both bolt patterns on the heads is a marketing ploy and does not mean there are actually any intakes suitable
for street use available

 

Is it a raised runner bowtie head? If so

http://www.gmpartsdirect.com/perform...CATID=995.html

Could also be a set of fastburns, they are drilled for a std and a vortec pattern

same manifold will bolt up to those (10051103)

 

I should have mentioned, a 3rd possible choice:

3. Take a Vortec intake and get the "traditional" bolt pattern drilled into it

This might or might not actually be possible, depending on how any particular intake might happen to be made, where the Vortec bolts go through it; might cost more in machine work than it's worth.

If it was me, I'd sell the heads and move on; and next time a "deal" appears, do this type of research BEFORE buying something, not AFTER. Never lose sight of the fact that, in this hobby as well as many other places in life, some things are designed only to be SOLD to people who THINK they WANT them, for reasons other than whether they actually WORK. The fact that "some people purchase" something is NO GUARANTEE that it is actually "A Good Idea".

 

Unfortunately, the intakes that have holes drilled for the Vortec bolt pattern aren't shaped the same in those areas so that would likely be a no-go.

As much as I love to do research, automotive stuff has never been an easy one to research. Especially since googling can bring up incorrect information. There is information on the internet regarding this scenario - though you have to be very specific to find it - ie: you really need to know there's an issue with this setup to find the results that state that this combination is bad news.

I think in all honesty the best/most realistic option would be (1) to get them drilled to fit a Vortec-specific intake manifold. The reason why is that not only are the intake ports located higher, but they are also canted which poses a major problem for lining up. I think the only way to use a pre-87 intake manifold would be to use one with raised ports, and then port match the heads - removing the slant to the intake ports. Dumb idea, that just doesn't sound like a good option.

So, it looks like the only logical answer is to drill the other holes and use a Vortec intake. Now I just need to get some info on the exact location to drill! ..this should be interesting..

 

Bigger problem will be getting the bolt angle correct.
Vortec intake bolts are vertical to the ground ; not to the head face as on pre '87 GEN 1 heads

As seen on this aftermarket Vortec TPI intake

 

just build a motor that can support the heads- aim for and honest 500+hp- and run a Bow Tie raised runner intake manifold..

if you can't afford that, then sell the heads to someone that is building a 500+hp monster and get a set of the proper vortec heads...

 

I've heard (never seen) the Victor Jr. covers the ports.

Post #6
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