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#21
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#22
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As far as Parts Place porting-the problem both of mine had was missing metal where it needed to seal, and one needed weld on the top of the ports.
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Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
#23
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It's not too uncommon to weld on factory intakes when you want to port match them to bigger heads.
It's done in the SBC world fairly often when using the factory DZ and LT1 intakes and sometimes on the BBC stuff as well. They were never known for having a bunch of meat in that area and when aftermarket heads are used with the runner raised, well it has to be done if you want a factory intake. |
#24
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Ask Steve C to post a pic of his original 70 RAIII iron intake, it's just as bad.
Pictures here in post #9 The subject of the thread was Stock intake manifold sealing. https://forums.maxperformanceinc.com...d.php?t=693767 .
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'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 ) Old information here: http://www.hotrod.com/articles/0712p...tiac-trans-am/ Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine) 5.14 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension https://www.youtube.com/watch?v=qDoJnIP3HgE |
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#25
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#26
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My bad a 72 not a 71
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#27
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In fact it was someone on this site that supplied an OEM casting to make the mold to repop those manifolds. |
#28
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I am currently watching the video linked in post #19.
I have heard of the core shift issues, and have also understood that some are better than others. I wholly agree with something mentioned early in the video; I think it's great that TPP is making a bunch of these unique Pontiac parts. What I don't get is why they can't(?) insist on better QC from their suppliers; In the context of these aluminum intakes, I would think that even though these were patterned after a factory part, (I would think at least that) they could have actually made them better. If an area is identified as being too thin, beef it up; If ports are obviously out of line, would it be too hard to get them at least closer?
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1970 Formula 400 Carousel Red paint on Black standard interior A no-engine, no-transmission, no-wheel option car. Quite likely one of few '70 Muncie three speed Formula 400's left. 1991 Grand Am: 14.4 @ 93.7mph (DA corrected) (retired DD, stock appearing) 2009 Cobalt SS: 13.9 @ 103mph (current DD; makes something north of 300hp & 350ft/lbs) |
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#29
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I'm not a casting guru but I tend to think it's probably an involved process to alter anything.
I agree, and I think if it were easy it would have been corrected along time ago. They've been this way since the beginning, many years. I'm also betting that since a person has to supply an OEM casting, they aren't likely going to possibly sacrifice one of their nice versions, hence the reason we have a repop that mimics the OEM port misalignment seen on a lot of factory intakes. So we get what we get. |
#30
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A lot has been covered in regards to this subject on this website. Some of the why's, when's and because have been explained.
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#31
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I would assume the intake uses shell cores for the voids, would be darn near impossible to cold set them with any sort of consistency. The molds for shells cores (can) cost a fortune, ditto for the intake pattern. When designing both, shrinkage needs to be taken into account, so one cannot simply “copy” an intake then cast it. I think cast iron has a lower shrinkage than aluminum. I believe there’s a formula to figure it out, depends on either weight/mass, length, or both.
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costs too much |
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#32
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Looking at the pics the 69 RAIV version looks nicer than the 71 HO version. I can cut, weld and grind. Sounds like a fun retirement project when I slow the car down but keep racing. But I would modify it for a 4150 carb most likely. |
#33
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If you can weld aluminum you are in good shape! Way lighter than a cast iron intake!
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Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
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#34
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thanks again everyone, great info. I knew this had been covered before but Im getting older and aluminum sounds much easier to lift. lol chuck
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#35
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#36
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So if the consensus is that quality of these castings are no worse than factory castings, then there's no reason not consider one. So then the question is do they perform better than a factory iron intake as cast, or would they need to be ported for any performance benefit?
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70 TA, 467 cid IAII, Edelbrock D-port heads, 9.94:1, Butler HR 236/242 @ .050, 520/540 lift, 112 LSA, Q-jet, TKX (2.87 1st/.81 OD), 3.31 rear https://youtube.com/shorts/gG15nb4FWeo?feature=share |
#37
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I think that this is a bit off:
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I believe what is being implied (certainly in the quote) is that all core shift is equal. But it is not. This is essentially a comparison of the worst to the repops. Also, now that I'm thinking about it again (I thought I mentioned this already, but cannot see the comment); I do seem to recall that the consensus was that these repops are all essentially the same part with revised part numbers; If my memory serves me, the original 1972 intake had the highest height for the plenum directly under the carburetor mounting flange - and these all measured as being based off the 1972 part (which I believe was also what GM did with later service replacement parts). I believe that generally the OEM intakes had the least core shift (or runner misalignment) and that the OEM 1969-1971 intakes had the best flow because of the lower plenum under the carb. Surely no OEM (or SR intake for that matter) required welding to seal up holes in the runner - as was the case in the intake from the video. As to the other query: Quote:
The intake runners were made taller to align with the intake runners of the 69-72 round port heads. I believe that even when ported, you need to match to the heads to maximize any gains. I am confident I will be corrected if I am off on any of that.
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1970 Formula 400 Carousel Red paint on Black standard interior A no-engine, no-transmission, no-wheel option car. Quite likely one of few '70 Muncie three speed Formula 400's left. 1991 Grand Am: 14.4 @ 93.7mph (DA corrected) (retired DD, stock appearing) 2009 Cobalt SS: 13.9 @ 103mph (current DD; makes something north of 300hp & 350ft/lbs) |
#38
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That's the exact problem the one brought to me had. By the time the ports were straightened out to get a decent match to the heads and gaskets, there was no more than .060" left for a gasket seal at the top of 3-4 of the ports. Welding the outside top would have effected the look of the manifold. Also the flanges would have needed to be set-up in the mill and surfaced. The cost to make these repairs would have been substantially more than the manifold cost. IMO, if they are going to cast a crappy, core shifted manifold in China, please leave plenty of material so it can be repaired without welding. That would be much easier to work with.
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#39
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#40
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They work well enough that I don't think twice about using one if you're looking for a stock appearance on a nice street/strip engine |
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