Re: "Stage II" porting....its not all the same
#13514
11/22/04 11:53 PM
11/22/04 11:53 PM
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Joined: Jul 2003
Posts: 12,132 Cleveland
sunroofgtx
I Live Here
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I Live Here
Joined: Jul 2003
Posts: 12,132
Cleveland
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Good question. How much difference is made ind match porting the intake ???
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Re: "Stage II" porting....its not all the same
[Re: sunroofgtx]
#13515
11/23/04 11:05 AM
11/23/04 11:05 AM
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Anonymous
Unregistered
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Anonymous
Unregistered
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For Mopar intake porting the other guys here should share their experience.
I can share what I know from comp heads and pro stock stuff.
In many cases it's good to have the intake opening very slightly smaller then the head opening. The small lip left helps tune the shock wave that travels the port.
On a head that may have too large a port for the engine combo, .. leaving the port opening small can also have a very good effect on port velocity. We used to run oval port intake manifolds on square port bog block Chevy heads and pick up .3 - .4 et all the time.
As for the rest of the manifold, .. porting & tuning on an all out head / intake combo is critical. The head & manifold together form ONE intake runner right? So the intake runner cross section & volume is just as important as the runner in the head.
On many combo's the gasket area, where the intake meets the head, becomes the smallest area of the entire intake runner.
A properly designed intake runner should not have the same size ( area & cross section ) all the way down. Just a strait pipe from the plenum to the valve wouldn't make power.
There has to be a little venturi in the port where it get's a little smaller to effect air speed. How far up or down the port this is located depends on the combo.
If you really want to know the entire airflow story in an engine, ..
flow the exhaust port with the header that it's going to run with, .. and the intake & carb on the intake side.
When you get this far into a project, .. it's a VERY good idea to turn the head around on the bench, push the air out of the bench into the intake, .. so you can do a velocity map of the airspeed coming out of the valve.
This is a good time to do wet flow since the set up on the bench is the same.
Curtis
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Re: "Stage II" porting....its not all the same
#13517
11/23/04 01:13 PM
11/23/04 01:13 PM
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Anonymous
Unregistered
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Anonymous
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Curtis: I build Jr. Drag engines and I have had similar experience with the ports and intake manifold. I made my intakes out of aluminum stock on my lathe. I would taper bore the intake at about 1.5 degrees over a 5" length. I only used round ports with the intakes for the ease of doing the ports. For example: I used a Mikuni carb with a 1.600" throttle bore with the valve seat having a I.D. of 1.500". I would turn down fender washers to the appropriate O.D. and use them for templates to keep the port shape. The Super Flow manual showed an ideal port shape and I used that as a guide. I guess now I will have to try this on some old V-8 heads and learn from there. Thanks for the info.
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Re: "Stage II" porting....its not all the same
[Re: BradH]
#13518
11/23/04 05:12 PM
11/23/04 05:12 PM
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Anonymous
Unregistered
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Anonymous
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Quote:
And for anybody interested, my SF-110 is now for sale under the Tools and Equipment For Sale section of the board.
Brad, why you selling the SF110, .. moving up to a bigger sucker????
Curtis
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Re: "Stage II" porting....its not all the same
#13519
11/23/04 09:37 PM
11/23/04 09:37 PM
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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
Taking time off to work on my car
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Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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Quote:
Quote:
And for anybody interested, my SF-110 is now for sale under the Tools and Equipment For Sale section of the board.
Brad, why you selling the SF110, .. moving up to a bigger sucker????
Curtis
I wish...
Nope, purely a case of economics. I haven't been doing much w/ the bench for quite a while now and am thinking the $ could be used better elsewhere at this point.
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Re: "Stage II" porting....its not all the same
[Re: BradH]
#13520
11/23/04 11:00 PM
11/23/04 11:00 PM
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Joined: Jan 2003
Posts: 14,528 So. Burlington, Vt.
fast68plymouth
OP
I Live Here
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OP
I Live Here
Joined: Jan 2003
Posts: 14,528
So. Burlington, Vt.
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Quote:
Quote:
Quote:
And for anybody interested, my SF-110 is now for sale under the Tools and Equipment For Sale section of the board.
Brad, why you selling the SF110, .. moving up to a bigger sucker????
Curtis
I wish...
Nope, purely a case of economics. I haven't been doing much w/ the bench for quite a while now and am thinking the $ could be used better elsewhere at this point.
i thought maybe it was because you discovered porting heads wasnt quite as much fun as you thought it would be
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: "Stage II" porting....its not all the same
[Re: fast68plymouth]
#13521
11/24/04 01:25 AM
11/24/04 01:25 AM
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Anonymous
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Anonymous
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Quote:
Brad, why you selling the SF110, .. moving up to a bigger sucker???? Curtis
I wish...
Quote:
Nope, purely a case of economics. I haven't been doing much w/ the bench for quite a while now and am thinking the $ could be used better elsewhere at this point.
Quote:
i thought maybe it was because you discovered porting heads wasnt quite as much fun as you thought it would be
I gave that stuff up some years ago. i never ever did think it was fun.
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Re: "Stage II" porting....its not all the same
[Re: fast68plymouth]
#13522
11/24/04 01:22 PM
11/24/04 01:22 PM
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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
Taking time off to work on my car
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Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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Quote:
Quote:
Quote:
Quote:
And for anybody interested, my SF-110 is now for sale under the Tools and Equipment For Sale section of the board.
Brad, why you selling the SF110, .. moving up to a bigger sucker????
Curtis
I wish...
Nope, purely a case of economics. I haven't been doing much w/ the bench for quite a while now and am thinking the $ could be used better elsewhere at this point.
i thought maybe it was because you discovered porting heads wasnt quite as much fun as you thought it would be
Not sure I ever thought it was "fun", but I like doing it -- as long as the numbers go UP, not DOWN. ![](/ubbthreads/images/graemlins/biggrin.gif)
However, I'm too freakin' slow at it to be able to earn a living w/ a grinder.
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Re: "Stage II" porting....its not all the same
[Re: AndyF]
#13524
11/25/04 04:16 AM
11/25/04 04:16 AM
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Anonymous
Unregistered
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Anonymous
Unregistered
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I got a six pack manifold from muscle motors several years ago with some 906 they ported. They offered to quote clean it up for a hundred. So I had them do it. I've never ran it. So I don't know if its worth while gain or not. I have a Eddy dual four intake that susposed to be the same as the six pack just a different top or so I've heard. I should look down the two and see what can just be visually observed in difference if anything.
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