Intake Manifold Modification - Page 2
Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds / (Old System)

Cadillac Technical Archive | Cadillac Dealers | Cadillac Reviews | Cadillac Dealer Reviews | Cadillac Vendors

CadillacForums.com is the premier Cadillac Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Page 2 of 2 FirstFirst 1 2
Results 16 to 26 of 26
500, 472, 425, 368 Discussion, Intake Manifold Modification in Cadillac Engine Technical Discussion; Originally Posted by bicentennialcadillac Here's what mine looks like. Just got it back today. That is perfect! In fact it ...
  1. #16
    Night Wolf's Avatar
    Night Wolf is offline Cadillac Owners 10000+ Posts
    Automobile(s): Unicycle
    Join Date
    Mar 2003
    Location
    Where I park it
    Posts
    11,009

    Re: Intake Manifold Modification

    Quote Originally Posted by bicentennialcadillac View Post
    Here's what mine looks like. Just got it back today.

    That is perfect! In fact it looks cleaner then mine does

  2. #17
    Night Wolf's Avatar
    Night Wolf is offline Cadillac Owners 10000+ Posts
    Automobile(s): Unicycle
    Join Date
    Mar 2003
    Location
    Where I park it
    Posts
    11,009

    Re: Intake Manifold Modification

    Those 2 holes with the channel is a passage that allows hotter exhaust air thru to warm up the intake air when the engine is cold. I left mine alone, didn't cut into them.

    The EGR is not compatible with this manifold. We plugged up the ports... my cruise control and everything else worked perfectly fine.

    My carb was rebuilt at the same time, my father rebuilt it, then tuned it... engine ran great, tho it would miss and be a little tempermental until it was warmed up... never got that issue fixed before it was wrecked.... drove from NY to FL perfectly fine though.

    One more thing, I do remember the A/C bracket not being correct, you'll need an A/C compressor bracket from a 472/500 to get it to bolt onto the 472 manifold as the 425 bracket is different.

  3. #18
    JohnDeville is offline Cadillac Owners Member
    Automobile(s): Cadillac
    Join Date
    Sep 2007
    Location
    Las Vegas, NV
    Posts
    29

    Re: Intake Manifold Modification

    This post has a couple pictures of the intake modification, but i would like to understand why or how the mod gives it more power. Anyone have any input? Thanks.

  4. #19
    fireman2101 is offline Cadillac Owners Member
    Automobile(s): '70 Cadillac Deville Convertible
    Join Date
    Dec 2006
    Location
    Lititz PA
    Age
    29
    Posts
    28

    Re: Intake Manifold Modification

    Ok it might just be me but i dont see any but the first two pictures. I also was wondering if anybody has done the mod at home or is it advised to go to a shop and get it done?

  5. #20
    Big Block Deville is offline Cadillac Owners Member
    Automobile(s): 74 Sedan DeVille
    Join Date
    Dec 2007
    Location
    portland OR
    Age
    42
    Posts
    26

    Question Re: Intake Manifold Modification

    Are there simpler tools to use than a miller to get that material out?
    I know I could saw a lot of that , but what about the cnc part?
    Any more pictures of other maybe less perfect mods that are currently in use?

  6. #21
    hearseman85 is offline Cadillac Owners Member
    Automobile(s): Cadillac
    Join Date
    Aug 2008
    Posts
    8

    Re: Intake Manifold Modification

    would this mod benefit my 368 engine?

  7. #22
    deVille33 is offline Cadillac Owners Connoisseur
    Automobile(s): 1977 Coupe (blue), 1977 Coupe (yellow), 1977 Coupe (green)
    Join Date
    Mar 2006
    Location
    Western Massachusetts
    Posts
    1,392

    Re: Intake Manifold Modification

    Quote Originally Posted by JohnDeville View Post
    This post has a couple pictures of the intake modification, but i would like to understand why or how the mod gives it more power. Anyone have any input? Thanks.

    By opening the area under the carb base you are increasing the plenum, which allows for a larger charge from the carb. This is an application taken from performance manifolds. The use of the 472 manifold will enhance fuel delivery, because it's a dual plane versus a single plane which is stock for 425.
    The single plane manifold is, generally a good application for high performance applications. In the 425, the single plane design was used because of the addition of the EGR passages. Cadillac didn't want to make the manifold sitting up any higher, because the height of the engine would have them redesigning the whole nose of the car. They also kept the plenum area relatively small to maintain fuel flow.
    The 472 manifold didn't have the EGR circuit and therefore allows for a cooler and denser fuel delivery to the cylinders. The dual plane also generally allows for smoother engine idle and better deliverly at low speeds.
    I'm not sure here, but the 472 manifold may lessen the upramping of fuel to the intake ports.
    With the mods they are making, they will most likely have to change the front circuit jets or rods in the carb.

  8. #23
    Adrian12's Avatar
    Adrian12 is offline Cadillac Owners Fanatic
    Join Date
    Jul 2006
    Location
    Treffen, Karnten, Austria, 109
    Posts
    138

    Re: Intake Manifold Modification

    Quote Originally Posted by hearseman85 View Post
    would this mod benefit my 368 engine?
    hi@all

    i know the thread is old, but i'm still interested in the same question on the stock intake manifold of the 368 v8-6-4 engine....

    would cutting out be benefit??

    thanks a lot to all experts

    adrian

  9. #24
    deVille33 is offline Cadillac Owners Connoisseur
    Automobile(s): 1977 Coupe (blue), 1977 Coupe (yellow), 1977 Coupe (green)
    Join Date
    Mar 2006
    Location
    Western Massachusetts
    Posts
    1,392

    Re: Intake Manifold Modification

    As I'm not familiar with the 368 or it's manifold's circuitry, I'm reluctant to answer this question. I would need more information.

  10. #25
    drmenard is offline Cadillac Owners Connoisseur
    Automobile(s): 95 fleetwood 81 deville
    Join Date
    May 2003
    Location
    Massachusetts
    Posts
    1,007

    Re: Intake Manifold Modification

    adrian12.... I think your wasting your time doing anything with the intake manifold... there is not much you can do with a 368... The only thing I ever did and got more power was put on 425 exhaust manifolds with the Y pipe from the 425... I did have to drill and tap a hole for the O2 sensor... I did not do it to get more power , I did it because the 368 exhaust manifold was cracked ...It was a pleasant surprise...

  11. #26
    Adrian12's Avatar
    Adrian12 is offline Cadillac Owners Fanatic
    Join Date
    Jul 2006
    Location
    Treffen, Karnten, Austria, 109
    Posts
    138

    Re: Intake Manifold Modification

    Quote Originally Posted by drmenard View Post
    adrian12.... I think your wasting your time doing anything with the intake manifold... there is not much you can do with a 368... The only thing I ever did and got more power was put on 425 exhaust manifolds with the Y pipe from the 425... I did have to drill and tap a hole for the O2 sensor... I did not do it to get more power , I did it because the 368 exhaust manifold was cracked ...It was a pleasant surprise...
    hi

    thx... but i've to waste time, cause getting parts in austria is nearly impossible and shipping such heavy parts to austria is very very expensive....

    so i have try to get everything done to have the car as good highway-daily-driver :P

    ciao
    adrian

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.
If you do not want to register, fill this field only and the name will be used as user name for your post.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Bookmarks

Cadillac Posting Rules

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
Read about Lincoln | Buick | Kia Forte Forum
Need products for your Cadillac? Check out your options at the links below:

custom floor mats | Cadillac Chrome and Black Chrome Wheels | window tinting