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youtube Vortec porting videos - total BS

General engine tech -- Drag Racing to Circle Track

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RevTheory
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Re: youtube Vortec porting videos - total BS

Post by RevTheory » Sat Mar 23, 2019 9:03 am

Let's all try to drop any prejudices from past discussions and move on with the sole intent of sharing ideas and learning. No one is "right" and no one is "wrong"; only sometimes different from each other. I'll go first.

Moving on. David, to draw from slo-svt's question; based on your previous Vortec head experiences, would you be able to predict what a port that flows like this one does, at the velocity it does, be able to do on the dyno in a street-oriented engine?

Are you seeing anything that may look great on the bench but prove to be not-so-great on the dyno? We all know the bench can whisper sweet nothin's in our ear.

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Re: youtube Vortec porting videos - total BS

Post by slo-svt » Sat Mar 23, 2019 9:34 am

RevTheory wrote:
Sat Mar 23, 2019 9:03 am
Let's all try to drop any prejudices from past discussions and move on with the sole intent of sharing ideas and learning. No one is "right" and no one is "wrong"; only sometimes different from each other. I'll go first.

Moving on. David, to draw from slo-svt's question; based on your previous Vortec head experiences, would you be able to predict what a port that flows like this one does, at the velocity it does, be able to do on the dyno in a street-oriented engine?

Are you seeing anything that may look great on the bench but prove to be not-so-great on the dyno? We all know the bench can whisper sweet nothin's in our ear.
David Vizard wrote:
Fri Mar 22, 2019 11:01 am

I am not trying to be disrespectful but that question was like asking you if you took a breath yesterday and which one was the deepest?

Without sorting through hundreds of dyno pulls on this I can say that gains such as seen on the heads in question are worth over 40 hp on an otherwise 300 or so HP 350.
DV
Rev he answered my question yesterday.
"I believe in the scientific method and one should have a healthy skepticism of things in general. From a scientific standpoint, you always look at thing probabilistically and not definitively."

Elon Musk

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Re: youtube Vortec porting videos - total BS

Post by RevTheory » Sat Mar 23, 2019 9:59 am

You're right- I needed to be more specific. Not enough octane in my blood yet.

David, in answering slo-svt's question, were you referring to the port you did the basic mods to in the video or the "super port" at the end?

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Re: youtube Vortec porting videos - total BS

Post by David Vizard » Sat Mar 23, 2019 12:24 pm

RevTheory wrote:
Sat Mar 23, 2019 9:59 am
You're right- I needed to be more specific. Not enough octane in my blood yet.

David, in answering slo-svt's question, were you referring to the port you did the basic mods to in the video or the "super port" at the end?
I am sure I would have been referring to the student ground port.
DV
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Re: youtube Vortec porting videos - total BS

Post by Carnut1 » Sat Mar 23, 2019 7:46 pm

Carnut1 wrote:
Thu Mar 21, 2019 9:53 pm
BradH wrote:
Thu Mar 21, 2019 9:21 pm
Just watched the Vortec video... whomever edited it cut out any shot of the finished intake guide modification, so it's not clear how much you removed.

I like the test where you clayed in the corner of the chamber where you stress not touching, and showed that it kept the intake flow from laying over at high lifts. Chamber do's and don'ts, regardless of head brand, interest me because that's the area where I have the least experience.
I would like to add that on my 083 thread my heads picked up flow by removing some shrouding in that corner. The 083 has a much lower ssr and different chamber design. Thanks, Charlie
IMG_7595.jpg
Resized_20190317_201335_9182.jpeg


Not the same but not too far off and I am interested in chamber characteristics. DV's video states leave the corner of the intake alone or even fill it. The pics are my 083 chamber after I did open up the corner of the chamber by intake valve. (Bottom) This had quite a change in cfm. The other pic is an EQ vortec I cleaned up in DV's shop. (Top ) Notice how open the chamber is in that corner, the curves there are very close to factory. The EQ vortec had a very strong flow curve with very little work. Now neither are GM vortecs but I think it is worth discussion. Thanks, Charlie
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Re: youtube Vortec porting videos - total BS

Post by BradH » Sun Mar 24, 2019 11:03 am

Charlie - After your previous response, I read your entire 083 thread. One key difference I see is the original 083 chamber intake seat region had basically no transition zone on the quench side of the seat. IIRC one of Darin Morgan's old threads on chamber design stated that was detrimental to pressure recovery. I believe your laying back the chamber in that location created a needed transition zone.

So my next question is... what is it about the as-cast OEM Vortec chamber that makes that specific area so sensitive? It looks like the aftermarket Vortec replacement head you worked on above "fixed" the issue by making the chamber effectively the same as DV's clay mod, assuming you didn't need to do much other than basic cleanup there. Thanks - Brad
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Re: youtube Vortec porting videos - total BS

Post by makin chips » Sun Mar 24, 2019 1:40 pm

Does the Vortec 4.3L V6 from last decade have these same chambers? Would these mods apply to those heads, also? Thanks.

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Re: youtube Vortec porting videos - total BS

Post by Carnut1 » Sun Mar 24, 2019 3:32 pm

makin chips wrote:
Sun Mar 24, 2019 1:40 pm
Does the Vortec 4.3L V6 from last decade have these same chambers? Would these mods apply to those heads, also? Thanks.
They are the same as the ones DV is working on in the video.
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Re: youtube Vortec porting videos - total BS

Post by David Vizard » Mon Mar 25, 2019 7:04 pm

I guess I must have struck a chord here with Power Tec 10 EP 5 that interested many people as this video has taken off even faster than my very controversial 128 cam formula video.
I want to thank all the ST posters that made complimentary comments and suggestions for bettering the video presentations.

thanks
DV
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Re: youtube Vortec porting videos - total BS

Post by 88bluestar » Tue May 14, 2019 8:07 pm

Being a guy trying to reduce cc in the chamber on my race engine to meet compression rules I find the video extremely important as to where to grind away and where not. I'm a novice so this helps a lot David, huge thanks.

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Re: youtube Vortec porting videos - total BS

Post by David Vizard » Tue May 21, 2019 2:59 pm

OK guys,
I have just come out of hospital from 2 weeks in intensive care from two brain surgeries (more on that in another thread) . That was followed by a further 3 weeks in hospital with a final release home last week. this is my first day down in the shop and on the computer taking a look at speed talk.

What do I find - this thread being dominated with arguments that are almost insignificant.

Guys, let me tell you from experience, life is both precarious and possible shorter than you may anticipate. Would it be too much to ask that we all be a little more polite, less clinical and a little more flexible with our opinions.

AS for the question of whether or not I had tested those Vortec mods let me say that my answer was based on the fact that for the last 50 years all the mods I write about are tested. I was under the illusion that anyone who read my stuff would know that so the question looked somewhat unnecessary.

With a 10.5/1 CR I have regularly seen 1.35 lbs-ft per cube with Vortecs ported along the lines put forth in the video.

Sorry If I ruffled any feathers here.

DV
David Vizard Small Group Performance Seminars - held about every 2 months. My shop or yours. Contact for seminar deails - davidvizardseminar@gmail.com for details.

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Re: youtube Vortec porting videos - total BS

Post by makin chips » Tue May 21, 2019 3:10 pm

Glad to have you back, David. Just wanted to wish you well on your continued recovery!

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Re: youtube Vortec porting videos - total BS

Post by David Vizard » Tue May 21, 2019 3:15 pm

makin chips wrote:
Tue May 21, 2019 3:10 pm
Glad to have you back, David. Just wanted to wish you well on your continued recovery!
Thank you Mr. Chips sir.
DV
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Re: youtube Vortec porting videos - total BS

Post by houser45 » Tue May 21, 2019 3:18 pm

David Vizard wrote:
Tue May 21, 2019 2:59 pm
OK guys,
I have just come out of hospital from 2 weeks in intensive care from two brain surgeries (more on that in another thread) . That was followed by a further 3 weeks in hospital with a final release home last week. this is my first day down in the shop and on the computer taking a look at speed talk.

What do I find - this thread being dominated with arguments that are almost insignificant.

Guys, let me tell you from experience, life is both precarious and possible shorter than you may anticipate. Would it be too much to ask that we all be a little more polite, less clinical and a little more flexible with our opinions.

AS for the question of whether or not I had tested those Vortec mods let me say that my answer was based on the fact that for the last 50 years all the mods I write about are tested. I was under the illusion that anyone who read my stuff would know that so the question looked somewhat unnecessary.

With a 10.5/1 CR I have regularly seen 1.35 lbs-ft per cube with Vortecs ported along the lines put forth in the video.

Sorry If I ruffled any feathers here.

DV
Just keep your knowledge flowing. I love watching your videos and reading your posts and hope one day to attend one of your classes.

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Re: youtube Vortec porting videos - total BS

Post by BradH » Tue May 21, 2019 3:21 pm

David Vizard wrote:
Tue May 21, 2019 3:15 pm
makin chips wrote:
Tue May 21, 2019 3:10 pm
Glad to have you back, David. Just wanted to wish you well on your continued recovery!
Thank you Mr. Chips sir.
DV
Peter O'Toole, IIRC... :lol:
One big happy PITA to everyone who knows me! :lol:

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