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Vortec heads drilled for 12 bolt intake issues?

Stomis

Stomis

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The vortec heads I bought were drilled for a 12 bolt intake by the PO. When I cleaned them up I notice that the smaller intake ports on the ends of the head had 2 beads of rtv on the top of the runner where the intake seals.

So after doing some googling I find ONE post on how its a bad idea to convert the vortec heads because the ports on the classic style intake will be mismatched and cause the intake manifold gasket to blow out over time.

So I figured the place to start solving this problem would be gasket matching the head and the intake. Does anyone have any experience with doing the vortec to traditional conversion on vortec heads or have any comments or advise?
 
basicly the vortec runners are taller.

old style are fatter.

why anyone drills/tapps for old to new i dont know ? ther is pleanty of intakes now for vortec.

i have seen some weld up the top of the intake at the runners and then hog it out to fit the vortec runners. but why ?

just get a vortec intake and be done with it.
 
sweetk30 said:
basicly the vortec runners are taller.

old style are fatter.

why anyone drills/tapps for old to new i dont know ? ther is pleanty of intakes now for vortec.

i have seen some weld up the top of the intake at the runners and then hog it out to fit the vortec runners. but why ?



just get a vortec intake and be done with it.
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Well the problem there is that the person that did it didnt leave the vortec holes intact.
 
Vortec heads suck unless they are aftermarket ones that are made thicker so they don't crack. For your issue though all you can do is find the correct gasket that matches the port of the head then transfer it to the intake and start port matching (you might find that you need to weld along the top edge of the intake in order to match the port so that it will still seal.

Also, the traditional style 12 bolt intake is MUCH better than the 8 bolt style as far as clamping force and not leaking. Why GM decided that it would be a good idea to use less bolts AND smaller bolts is beyond me. :dunno:
 
K85 Octane said:
I'm pretty stupid when it comes to parts and stuff. If I have an older 400sb, using Vortec heads, EGR, and Q-jet carb.... which manifold should I use? please :)

http://www.edelbrock.com/automotive_new/mc/manifolds/chevy/performer-sb.shtml
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Well, that depends on which intake bolt pattern the Vortec heads have (they are made with either pattern now). Also, Vortec heads DO NOT have an exhaust crossover like every other SBC head so if you need EGR you have to buy a "kit" to plumb the EGR off of the exhaust pipe.

Here is a Vortec head with BOTH patterns drilled in the head. http://www.summitracing.com/parts/NAL-25534421/?rtype=10
 
4X4HIGH said:
Vortec heads suck unless they are aftermarket ones that are made thicker so they don't crack. For your issue though all you can do is find the correct gasket that matches the port of the head then transfer it to the intake and start port matching (you might find that you need to weld along the top edge of the intake in order to match the port so that it will still seal.

Also, the traditional style 12 bolt intake is MUCH better than the 8 bolt style as far as clamping force and not leaking. Why GM decided that it would be a good idea to use less bolts AND smaller bolts is beyond me. :dunno:
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By "vortec heads suck unless aftermarket" I take you mean 12 bolt vortec heads due to the thin area?

I've heard the opposite about the vortec pattern.That the angle of the bolts has something to do with fastening it better plus they come stock with a MUCH better gasket set.

Anyway the porting and welding idea was what I was pretty sure I'd have to do.

And k85 nice hijack :p From everything I've read edelbrocks air gap intake is the best all around intake on the market.
 
Can the original holes be repaired? Redrilled and helicoiled would be easier than fabbing an old style intake to fit.
 
496truck said:
Can the original holes be repaired? Redrilled and helicoiled would be easier than fabbing an old style intake to fit.
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Dont know I've gotta bust the JB weld out of them. They may very well be intact actually after looking at them again.

I may just save for torker for a later turbo idea and get an RPM airgap intake.
 
Stomis said:
By "vortec heads suck unless aftermarket" I take you mean 12 bolt vortec heads due to the thin area?

I've heard the opposite about the vortec pattern.That the angle of the bolts has something to do with fastening it better plus they come stock with a MUCH better gasket set.

Anyway the porting and welding idea was what I was pretty sure I'd have to do.

And k85 nice hijack :p From everything I've read edelbrocks air gap intake is the best all around intake on the market.
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No, Im guessing he means the vortec heads that came in the 96-00 OBS trucks. They are a lightweight casting and like to crack from what I hear.
 
79rustyk10 said:
No, Im guessing he means the vortec heads that came in the 96-00 OBS trucks. They are a lightweight casting and like to crack from what I hear.
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I have never heard of people having issues with vortec heads. Most people praise them as the best factory head ever produced. I mean that doesnt mean they might not be prone to cracks in a given situation but I've never seen anyone say "Stay away from those vortec heads they crack all the time!"
 
Stomis said:
I have never heard of people having issues with vortec heads. Most people praise them as the best factory head ever produced. I mean that doesnt mean they might not be prone to cracks in a given situation but I've never seen anyone say "Stay away from those vortec heads they crack all the time!"
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Well if you haven't heard me say it then I will now just for you, stay away from the Vortec heads they crack all the time. :D

Seriously though, when I was doing all the work for the 3 GM dealers in town EVERY Vortec head they sent me was cracked. I have NEVER seen a Vortec head yet that wasn't cracked UNLESS it was an aftermarket Vortec head with the thick castings.
 
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