[C2] Small block aluminum intake?
#1
Race Director
Thread Starter
Member Since: Nov 2003
Location: Cottonwood AZ
Posts: 10,698
Received 3,048 Likes
on
1,934 Posts
C1 of Year Finalist (performance mods) 2019
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
https://www.summitracing.com/oh/parts/edl-2101
The following 3 users liked this post by 63 340HP:
#3
Race Director
Thread Starter
Member Since: Nov 2003
Location: Cottonwood AZ
Posts: 10,698
Received 3,048 Likes
on
1,934 Posts
C1 of Year Finalist (performance mods) 2019
#5
Race Director
Thread Starter
Member Since: Nov 2003
Location: Cottonwood AZ
Posts: 10,698
Received 3,048 Likes
on
1,934 Posts
C1 of Year Finalist (performance mods) 2019
#6
Le Mans Master
Member Since: Nov 2015
Location: Really Central IL Illinois
Posts: 5,207
Received 1,534 Likes
on
1,036 Posts
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 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
#7
Race Director
Thread Starter
Member Since: Nov 2003
Location: Cottonwood AZ
Posts: 10,698
Received 3,048 Likes
on
1,934 Posts
C1 of Year Finalist (performance mods) 2019
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 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
#8
Race Director
Thread Starter
Member Since: Nov 2003
Location: Cottonwood AZ
Posts: 10,698
Received 3,048 Likes
on
1,934 Posts
C1 of Year Finalist (performance mods) 2019
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 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 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.
#9
Race Director
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
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
#10
Race Director
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
#11
Team Owner
Member Since: Nov 2005
Location: Beach & High Desert Southern California
Posts: 25,489
Received 2,339 Likes
on
890 Posts
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 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 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).
#12
Team Owner
Member Since: Nov 2005
Location: Beach & High Desert Southern California
Posts: 25,489
Received 2,339 Likes
on
890 Posts
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.
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.
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
#13
Drifting
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
https://www.summitracing.com/oh/parts/edl-2101
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.
#14
Race Director
Thread Starter
Member Since: Nov 2003
Location: Cottonwood AZ
Posts: 10,698
Received 3,048 Likes
on
1,934 Posts
C1 of Year Finalist (performance mods) 2019
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.
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.
#15
Drifting
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.