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[C2] Small block aluminum intake?

Old 12-04-2018, 07:07 PM
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68hemi
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Default Small block aluminum intake?

Has anyone done a side by side comparison of the intake in the link below for the height of it and a factory original aluminum manifold? Or does Edelbroch make another one that is the same height as the factory 327 aluminum manifold?

https://www.summitracing.com/oh/parts/edl-2101
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Old 12-04-2018, 08:10 PM
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I posted the spreadsheet before, but the Carb Ht column in this image gets you the answer (4.6 in).

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Old 12-04-2018, 08:21 PM
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Originally Posted by 63 340HP View Post
I posted the spreadsheet before, but the Carb Ht column in this image gets you the answer (4.6 in).


THANKS!
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Old 12-04-2018, 08:56 PM
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I used the 2101 on my 59 with a Quadrajet. Have about 3/8” clearance from the wing nut to hood.


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Old 12-05-2018, 03:57 PM
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Originally Posted by 59BlueSilver View Post
I used the 2101 on my 59 with a Quadrajet. Have about 3/8 clearance from the wing nut to hood.


Thanks but I am looking for the clearance under a stock small block in a C2 with a 1850S carb. that is the same as a stock 1965 350 h.p. intake and carb.
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Old 12-05-2018, 05:38 PM
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Here is the heights I found:

I am swapping the intake on the 68RS to an Eldebrock C3B as I want to use the 3890490 GM intake on R66.
I found they are both the same height within 1/8” - 4 1/8” vs 4-1/4”. It surprised me that the 3890490 was also used in Chevelles and Camaros and other 350 hp performance cars as well as Corvette.

Looks like they now call it the C3BX. My post is down near the bottom of the page.

Ron
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Old 12-05-2018, 05:45 PM
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Originally Posted by R66 View Post
Here is the heights I found:

I am swapping the intake on the 68RS to an Eldebrock C3B as I want to use the 3890490 GM intake on R66.
I found they are both the same height within 1/8 - 4 1/8 vs 4-1/4. It surprised me that the 3890490 was also used in Chevelles and Camaros and other 350 hp performance cars as well as Corvette.

Looks like they now call it the C3BX. My post is down near the bottom of the page.

Ron
I can't find either one of those numbers when I do a search on Summit for Edelbrock intakes?
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Old 12-05-2018, 06:12 PM
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Originally Posted by R66 View Post
Here is the heights I found:

I am swapping the intake on the 68RS to an Eldebrock C3B as I want to use the 3890490 GM intake on R66.
I found they are both the same height within 1/8 - 4 1/8 vs 4-1/4. It surprised me that the 3890490 was also used in Chevelles and Camaros and other 350 hp performance cars as well as Corvette.

Looks like they now call it the C3BX. My post is down near the bottom of the page.

Ron
I just spoke with Edelbrock's tech line and the C3B or C3BX were gone in the 70s so those are OLD intakes. They said that the correct replacement intake for either a 365 or 350 h.p. intake is their 2101 which is 4.050" high and that makes the chart in this thread wrong with regards to the 2101.

I have been all over the Net today trying to find info on the RIGHT intake manifold as a replacement for the 365/350 h.p. manifolds and there is a lot of incorrect info floating around out there.
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Old 12-05-2018, 06:28 PM
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That stock C1 type air cleaner is very forgiving when it comes to hood clearance, BUT, it sits so low over the carb that it strangles a (well breathing)* 327 or larger over 4500 RPM. The 1" high filter element is the culprit. Having the top so close to the carb venturi inlet probably doesn't help either.

And that isn't opinion, it is fact, as observed by watching the MAP readout on my EFI go from ~ambient pressure inside the air cleaner at 4000-4500 RPM to about 10"-12" of vacuum at 6000-6500 RPM at WOT.

*massaged Bowtie heads and headers. May not be an issue with stock heads on a 327.

Doug

Originally Posted by 59BlueSilver View Post
I used the 2101 on my 59 with a Quadrajet. Have about 3/8 clearance from the wing nut to hood.


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Old 12-05-2018, 06:41 PM
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The Weiand Stealth manifolds are no longer made, but does clear the hood in my '62 with a Street Avenger carb and a dropped base air cleaner with (I think) 2 3/4" filter
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Old 12-05-2018, 07:12 PM
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Originally Posted by R66 View Post
Here is the heights I found:

I am swapping the intake on the 68RS to an Eldebrock C3B as I want to use the 3890490 GM intake on R66.
I found they are both the same height within 1/8 - 4 1/8 vs 4-1/4. It surprised me that the 3890490 was also used in Chevelles and Camaros and other 350 hp performance cars as well as Corvette.

Looks like they now call it the C3BX. My post is down near the bottom of the page.

Ron
The C3B was Edelbrock's original high flow dual plane design with an open carb flange base and the center divider with a notch cut out, designed for the (then) new Holley 900 cfm 3-barrel.secondary throttle plate for 7500+ rpm performance on long oval tracks. The C3BX is the same manifold with the center divider intact for a traditional 4-barrel (usually, many C3BX manifolds have the divider notch because it was considered to improve high rpm power, similar to the cut down L88 manifold divider).

The C3B series manifolds are a higher flowing, improved large tapered runner design, over the prior 4-hole flange C-4B (up to 900 cfm for the C3B, compared to ~650cfm max for the C-4B). Edelbrock's second and first (respectively) aluminum aftermarket single 4-barrel manifolds for the SBC (with both manifolds designed with the assistance of Bob Joehnck from Santa Barbara).

When Jim McFarland designed the single plane manifolds for Edelbrock the resulting higher airflow and high rpm performance displaced the need for a high flow dual plane like the C3BX. All subsequent Edelbrock dual plane manifolds have smaller runners and taller carb pad heights designed for under 6500 rpm performance (even the current PM Air-Gap top of the line models).
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Old 12-05-2018, 07:35 PM
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Originally Posted by 68hemi View Post
I just spoke with Edelbrock's tech line and the C3B or C3BX were gone in the 70s so those are OLD intakes. They said that the correct replacement intake for either a 365 or 350 h.p. intake is their 2101 which is 4.050" high and that makes the chart in this thread wrong with regards to the 2101.

I have been all over the Net today trying to find info on the RIGHT intake manifold as a replacement for the 365/350 h.p. manifolds and there is a lot of incorrect info floating around out there.
Apparently Hot Rod magazine listed the "B" (rear of pad) height in their comparison spreadsheet.

For example the 7101 RPM manifold heights are A=4.20 / B=5.25 (0.70 taller than the 2101, per Edelbrock), an average height of 4.27" (again per Edelbrock, but the math gives us 4.725", so even Edelbrock's web page has a transposed number typo). Hot Rod's list height is 5.25."

Another example of why we should never trust Journalists, or web page authors, to communicate technical information correctly
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Old 12-07-2018, 12:05 AM
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Originally Posted by 68hemi View Post
Has anyone done a side by side comparison of the intake in the link below for the height of it and a factory original aluminum manifold? Or does Edelbroch make another one that is the same height as the factory 327 aluminum manifold?

https://www.summitracing.com/oh/parts/edl-2101
Attached is a summary table that I think I have posted before. Some people who have installed the Z28 intake in a C2 find that it clears the hood, while others find that it interferes very slightly with the hood. So, the 4.69" height of the Z28 intake represents about the most that can be expected for a C2. There are several Edelbrock intakes that are less than 4.69".

Note that some additional hood clearance can be obtained by raising the body a bit. I added a few shims at each body mount to gain some additional hood clearance for the Z28 intake.
Attached Images
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Old 12-07-2018, 02:19 AM
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Originally Posted by GearheadJoe View Post
Attached is a summary table that I think I have posted before. Some people who have installed the Z28 intake in a C2 find that it clears the hood, while others find that it interferes very slightly with the hood. So, the 4.69" height of the Z28 intake represents about the most that can be expected for a C2. There are several Edelbrock intakes that are less than 4.69".

Note that some additional hood clearance can be obtained by raising the body a bit. I added a few shims at each body mount to gain some additional hood clearance for the Z28 intake.
So which of the Edelbrock intakes do you think would give the best performance on a 350 h.p. engine with factory type carb?
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Old 12-07-2018, 02:13 PM
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Originally Posted by 68hemi View Post


So which of the Edelbrock intakes do you think would give the best performance on a 350 h.p. engine with factory type carb?
Before commenting on performance comparisons, I want to mention that the Edelbrock "carb height" dimensions I showed in my comparison came from the Edelbrock web site. Some of the above posts have indicated that even Edelbrock's information contains some errors. So, if you decide to get an Edelbrock intake based on the info in my comparison, you should double-check the carb height with Edelbrock.

For the information I posted about the L79 and Z28 intakes, I'm quite certain that is correct because I measured it myself and triple-checked the results. So, the following information is pretty reliable:

1) The '490 "carb height" measurement is 4.19" and the Z28 measurement is 4.69"
2) The Z28 intake fits fine on some C2 Corvettes and interferes just a little bit on other C2 Corvettes.
3) A small amount of hood interference can be fixed with some extra body shims or an alternate air cleaner

My conclusion is that any intake that has a carb height of 4.69" or less can be used on a C2 Corvette. In practice, the difference between the Z28 height of 4.69" and the (stated) Edelbrock Performer RPM height of 4.72" is so small that it probably doesn't rule out the Performer RPM.

So, to answer your question about Edelbrock intakes, I think the best performance would be achieved with the Performer RPM. You might also want to consider using the GM 3917610 intake that was used on the 1967 Z28. This intake (and others in the same family of Z28 and LT1 intakes) is widely regarded to be the best-performing small block intake that GM ever made.

An additional feature of the 1967 Z28 intake is that the front end of it (the portion that is visible with the air cleaner on) is virtually identical to the '490 intake. Look closely at the comparison photo below and you will see that the thermostat housing, water temp sensor hole, oil fill tube angle, and even the Winters logo are identical to the '490. The Z28 intake also has all the necessary bosses in the back for the C2 hardware, and it even has the "choke stove" next to the carb if you want to use that.

My suggestion would be to use the Performer RPM if a stock appearance is not important, but consider the more expensive 1967 Z28 intake if you want to have the same general appearance of the '490.




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