School me on Intake compatability, and modifications.

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cpearce

cpearce

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I just recently ended up with a parts lot of Gen 3 Hemi stuff. One of the items is an NOS Edelbrock 7528 dual quad intake manifold for 2008 and earlier 5.7 engines. This intake uses oring seals on each port face.

Can anyone tell me if this can be opened up for use on Eagle, 6.1 or 6.4 heads? If it can, i assume one would eliminate the oring type seal and use flat intake gaskets? This gen 3 Hemi stuff is new turf for me. I have searched the net and found many articles of 6.4 intakes on early 5.7 heads, using port adapters, but not earlier intakes on larger port heads.
 
I believe the port shapes are a little different. The early 5.7 stuff has a small notch for the injectors and is a little more rectangular as I recall. I think the 6.1 stuff is pretty square and was more or less the design they kept on all the next stuff since. I almost want to say the 6.1 port was even a tad smaller, but that might not be right. O-ring vs flat gasket is probably a non-issue. My ModMan intake never had o-ring grooves, though I wish it did. It just used some phenolic style gaskets to seal things up. It would be nice if they could be adapted as that is one thing that keeps me from using a newer engine if I ever had to replace mine.

I would love it if someone had every version of head that was made and lined them all up in a row for a picture to compare intake and exhaust ports. I almost thought about posting and asking that recently when I started searching myself. Anyone have an early 5.7, Eagle 5.7, 6.1, 6.4, and 6.2 (Hellcat) head all sitting in their shop? I think the Hellcat head is just a 6.4 head, so might just be the 4 to compare (early 5.7, late 5.7, 6.1, and 6.4).
 
Map63Vette said:
I believe the port shapes are a little different. The early 5.7 stuff has a small notch for the injectors and is a little more rectangular as I recall. I think the 6.1 stuff is pretty square and was more or less the design they kept on all the next stuff since. I almost want to say the 6.1 port was even a tad smaller, but that might not be right. O-ring vs flat gasket is probably a non-issue. My ModMan intake never had o-ring grooves, though I wish it did. It just used some phenolic style gaskets to seal things up. It would be nice if they could be adapted as that is one thing that keeps me from using a newer engine if I ever had to replace mine.

I would love it if someone had every version of head that was made and lined them all up in a row for a picture to compare intake and exhaust ports. I almost thought about posting and asking that recently when I started searching myself. Anyone have an early 5.7, Eagle 5.7, 6.1, 6.4, and 6.2 (Hellcat) head all sitting in their shop? I think the Hellcat head is just a 6.4 head, so might just be the 4 to compare (early 5.7, late 5.7, 6.1, and 6.4).
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And how do you like your modman? I've seen very mixed reviews. Considering one for my 6.1 based 426 stroker with Apache heads.
 
cpearce said:
And how do you like your modman? I've seen very mixed reviews. Considering one for my 6.1 based 426 stroker with Apache heads.
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Mixed bag for sure. I bought it originally because it was about the only carb intake on the market back when I did my swap. I never could get my carb tuned to work with it, but I also didn't spend a ton of time. It just had a bad habit of falling on its face whenever you stabbed the throttle. It would roll into it okay, but hard hits just stalled the engine entirely. I was running a Carter AFB at the time and almost got a Holley double pumper, but I think I needed a spacer to make the linkage clear.

Long story short, drilled it for EFI and have been happy enough with it since then. Haven't had any real problems since then other than a less than ideal oil fill setup.
 
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@cpearce

Here are a couple pics of the Edelbrock dual four intake with a Cometic Eagle/6.1 gasket for reference. You can see it's a pretty significant mis match on the gasket sealing surfaces, let alone the actual port window. There's a bunch of different ways to skin this cat to make it work, but it can be done.
 
Wow, those are some big ports. Forget what I said about the 6.1 potentially being smaller, lol. So it sounds like the 6.1 and Eagle 5.7 are the same at least. Does anyone know what the 6.4 looks like and whether it shares the same ports? I assume exhaust is probably similar as well (6.1/Eagle being the same and different from early 5.7), but is it as bad of a difference as the intake?

I've found I have this magical ability to end up with parts and cars that are one year only, which always makes it fun to find things. My 67 Dart isn't too bad for one year stuff so far (windshield gasket is the big one, but those are finally being made now, window cranks are the other one I know of off the top of my head, but just aesthetic). My early 5.7 isn't exactly one year only, but does seem to still be the odd one out of the bunch of all the 3G Hemi stuff. If I can reuse the headers at least I wouldn't mind a new intake so much as I would probably just keep a factory one if I ever did an engine swap, but I do like my carb style throttle body for the fun of it.
 
The 6.4 is much the same as Eagle 5.7/6.1. May be slightly larger. The early exhaust are smallest. The rest are the D shape and aproximately same size.
 
408 swinger said:
View attachment 1716344506View attachment 1716344508
@cpearce

Here are a couple pics of the Edelbrock dual four intake with a Cometic Eagle/6.1 gasket for reference. You can see it's a pretty significant mis match on the gasket sealing surfaces, let alone the actual port window. There's a bunch of different ways to skin this cat to make it work, but it can be done.
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Wow, that is quite a difference for sure. Thank you for posting this. At the end of the day perhaps this intake will be a choking point for a 426 ci stroker?
 
cpearce said:
Wow, that is quite a difference for sure. Thank you for posting this. At the end of the day perhaps this intake will be a choking point for a 426 ci stroker?
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Maybe so without porting. Would take more than a "simple" port match. Getting that deep into it, I would have the gasket grooves welded up, then start the porting process.
 
408 swinger said:
Maybe so without porting. Would take more than a "simple" port match. Getting that deep into it, I would have the gasket grooves welded up, then start the porting process.
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And after checking mine tonight when I got home, I'm curious I'd there is enough meat there to work with. I'm thinking the runners may need to be built up where they meet the flange.

It is a shame the Modman from Indy get such poor reviews. This scenario leads one to wonder which is the better route, welding and port matching the Edelbrock, or creating a divider in the Modman to promote distribution and carb signal? I've not found much info on the Modman on engines over 392 ci., perhaps the Modmans shortcomings reduce as displacement increases?
 
cpearce said:
And after checking mine tonight when I got home, I'm curious I'd there is enough meat there to work with. I'm thinking the runners may need to be built up where they meet the flange.

It is a shame the Modman from Indy get such poor reviews. This scenario leads one to wonder which is the better route, welding and port matching the Edelbrock, or creating a divider in the Modman to promote distribution and carb signal? I've not found much info on the Modman on engines over 392 ci., perhaps the Modmans shortcomings reduce as displacement increases?
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I have no experience with the Mod manifolds. But, with that huge, open plenum, I can understand why a single carb application is dog ****. Dual carbs might be better.
 
408 swinger said:
I have no experience with the Mod manifolds. But, with that huge, open plenum, I can understand why a single carb application is dog ****. Dual carbs might be better.
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Oh for sure, I wouldn't entertain the thought of a single carb on one. This is exactly my dilemma, I wish to run dual quads, eventually dual EFI on a new Gen Hemi, but don't want it to be a pooch. If I were running a single carb I wouldn't be entertaining this discussion.
 
cpearce said:
Oh for sure, I wouldn't entertain the thought of a single carb on one. This is exactly my dilemma, I wish to run dual quads, eventually dual EFI on a new Gen Hemi, but don't want it to be a pooch. If I were running a single carb I wouldn't be entertaining this discussion.
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F it, go with the Holley Hi-Ram! :lol:
 
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