[Formulajones]

Originally Posted by jhein

Here's a video review that shows how bad the ports can be:

https://youtu.be/lrQFB-hNKqo?si=zxAUmsBbvflCmVOc&t=299

Ask Steve C to post a pic of his original 70 RAIII iron intake, it's just as bad.

[Skip Fix]

Originally Posted by Dragncar

How much are those things ? Has anyone ever taken one and done the full blown Cliff/SD Performance cutting and grinding like they do with stock iron intakes ?
That might be kinda cool.
I have a new Tig welder, nice set of ported 197s and a giant Thermo Quad. Maybe to the welding and fitting to run a 4150 carb like I have seen done. Lot easier than the iron intakes I have seen.
Might be a fun project.

Mine had SD do that.
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.

[Formulajones]

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.

[Steve C.]

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


.

[promptcritical]

Originally Posted by Formulajones

I've been running a repop RAIV intake for a few years now. I found nothing wrong with it, was no worse than the factory iron piece I pulled off. In fact these repop casting were done using an original OEM manifold, they were never really that perfect either if you've looked at enough of them.

As far as performance, been racing the car for 25 years with the original iron intake. Switching to the repop RAIV intake did absolutely nothing to ET or MPH, it runs "THE SAME"

The only reason for the change was knowing in the future I'd be building a RAIV clone for the car and figured I'd grab an intake while they were still available. Decided to just throw it on the car a few years back to experiment with a couple other ideas. One of those being how the heat cross over acts in a daily driver pump gas situation in the Arizona heat, since I daily drive this car as well.

Happy to report the separate heat cross over certainly helps with heat soak and hot starts, keeps the intake cooler, all while keeping my divorce choke functional. And on the cold winter days where it's in the teens in the mornings, there are no drivability issues at all.

On a side note, the 455HO I built a few years ago, had an OEM 71 HO intake on it and the ports weren't any better on that than my repop piece, which is said to be patterned off of it anyway, and I could see the similarities. That engine went on to make 507/571 on the dyno with that intake in place sitting on top of ported HO 197 heads by Dan Barton, and no modifying to the intake ports was needed. That was through the stock cast RA exhaust manifolds as well.

So the intake does work well and can support some HP right out of the box.

Larry, I think you're referencing my motor the you built. The heads are '72 7F6s. Not to pick nits. LOL

[Formulajones]

Originally Posted by promptcritical

Larry, I think you're referencing my motor the you built. The heads are '72 7F6s. Not to pick nits. LOL

My bad a 72 not a 71

[Formulajones]

Originally Posted by Steve C.

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


.

Thanks Steve, I figured they were floating on the site somewhere. Always worth mentioning when brought up as people seem to forget and think this is a repop casting issue when it's clear the oem castings weren't anywhere close to perfect either, and not just oem aluminum, but the cast iron pieces as well.
In fact it was someone on this site that supplied an OEM casting to make the mold to repop those manifolds.

[unruhjonny]

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?

[Formulajones]

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.

[PAUL K]

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.

[rolling money pits]

Originally Posted by Formulajones

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.

It’s quite involved, from initial design to, if needed, altering. I have no idea on how TPP casts, or has cast, the intakes in question. I’m only familiar with green sand/snap molding and using cold set for molds. Cores…cold set or shell cores.

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.

[Dragncar]

Originally Posted by Skip Fix

Mine had SD do that.
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.

They are only 300$, cheap these days.
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.

[Skip Fix]

If you can weld aluminum you are in good shape! Way lighter than a cast iron intake!

[BLUE TA]

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

[Formulajones]

Originally Posted by Dragncar

They are only 300$, cheap these days.
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.

Thanks for the price update, I haven't looked. You're right, $300 is cheap. Compare that to a lot of Eddy intakes on the market and it looks like a bargain. We are lucky they are even available. A bunch of desirable intakes for other brands aren't repopped like this one.

[jhein]

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?

[unruhjonny]

I think that this is a bit off:

Originally Posted by jhein

So if the consensus is that quality of these castings are no worse than factory castings, then there's no reason not consider one.

I think the consensus is that factory ones were not perfect, and that core shift (if that's what we might call it) can be observed on them all;
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:

Originally Posted by jhein

... 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?

I believe the consensus is: NO
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.

[mgarblik]

Originally Posted by Skip Fix

Mine had SD do that.
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.

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.

[Ram Air IV Jack]

Originally Posted by mgarblik

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.

Yup, Chinese parts man!!! You can get decent ones though and make them work but the quality control in China is terrible as reported here. Even if you find an OEM intake for $$$$, some slob could have worked on the ports and made it almost unusable. Finding a virgin OEM part is the best bet to get the correct fit but the cost can be a deciding factor to go with an overseas part.

[Formulajones]

Originally Posted by jhein

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?

I've tested the factory iron against a repop RAIV on my 70 RAIII bird back to back and there is no difference in performance. The car runs exactly the same. Duplicated ET and MPH with it. And I've had them on the dyno a couple times, they'll support over 500hp right out of the box.

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