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need Weber Carb info

Discussion in '1965-1970 Shelby Mustang GT350 & GT500' started by zrayr, Aug 11, 2007.

  1. zrayr

    zrayr Well-Known Member

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    I'm considering putting a Weber carb induction on my GT-350. I really would like to gather some "real life" experiences beforehand from those who have gone down this path. Anyone who has had personal experiences with this type of set-up, good or bad, please get in touch with me. I am particularly interested in:
    1) direct comparisons between the IDA and IDF systems
    2) comparisons between the original Cobra parallel manifold type and the the newer "mirror image carb mounting" type of manifold.
    3) experiences on small blocks, specifically 289 Hi-Po engines with more or less stock internals.


    Z. Ray
    zrichter@austin.rr.com
     
  2. JamesFee

    JamesFee Well-Known Member

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    Z.Ray,
    You are in for a wild ride in more than one sense of the term, should you choose to go with Webers. I will start off by saying that they are not for the faint of heart.

    1. - I am sorry but I cannot offer a comparison of the IDA vs IDF types - I went broke after the IDA's :laf:

    2 - The original manifolds might as well be made of "Unobtainium". If you have the patience of a Saint you can scour Ebay and your local swaps but I have had no such luck in the last two years. The "Next Best Thing" would be to find a Blue Thunder casting with Cobra lettering. These are almost as hard to find as the real deal and can be told by the mirror image carb mounting you mention. Currently, the commonly available manifolds are available for either Weber type, and either Cobra water neck or integrated thermostat.

    I purchased an Inglese system with the understanding that it would have the Cobra cast into the manifold.... it did not arrive that way and I will leave it at that. NOTE: They have been bought by FAST a division of the COMP Performance Group, so I would hope that things will improve. They were looking to a new run of the Cobra cast logo manifolds - in April they were quoting 6 months out. These are the mirror image design, though if you want a more original appearance, they offer a set of "reversing plates" which turns the carbs around on one side of the intake so that the fuel harness runs "outboard" of all the carbs.

    An excellent source of information would be to search and lurk over at the Club Cobra forums - there are several very knowledgeable guys over there with many war stories in the setup on both small and bigblocks.

    3. I am on my second smallblock (289) installation. You asked about "stock" internals - what you need to be aware of is that Webers are a "non-plenum induction system". There is no common area for the air/fuel mixture to congregate, each barrel feeds one and only one cylinder (that's why the carb balancing need to be done diligently so they all are performing identically). That means the stock HiPo cam with its wild overlap only spits gas back out the carbs at you. You should look at a cam ground for this type of installation - and complementary to that, you should be prepared to have your distributer recurved to match the needs of the cam and the Webers.

    I hope that this helps. :thumbsup:
     
  3. zrayr

    zrayr Well-Known Member

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    first, thanks for he detailed reply, second, what cam(s) are you using?Are there any books you recomend?

    Z. Ray
     
  4. JamesFee

    JamesFee Well-Known Member

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    Z.Ray

    My first motor was built with the cam recommended by Inglese - It was a CamTechniques solid lifter flat tappet cam. I was happy with the performance and essentially stuffed it into Blue's original motor (Chuck Barbero at Distributor Dynamics in Brownsville,CA did the distributor work). I suffered an early engine failure (3 mushroomed tappets). Since I did the work myself, I was not willing to bad mouth the parts (it's a poor tradesman who blames his tools) but it was somewhat similar to a near-death experience with my numbers matching block.

    For the rebuild, I found another 289 block to "run" and rebuilt the original (which is now on an engine stand in the garage).

    No longer worried about irreparably changing my block, my new motor was built to be a true GT as in Grand Touring; I wanted it to be powerful and reliable enough for a trip down the Blue Ridge Mountain Parkway. Toward that end, I had the block machined for a hydraulic roller cam from Comp Cams. I am very happy with what I have and it while it produces gobs of power it can idle very nicely if need be and requires no maintenance.

    I guess the point of this is to know what *you* want from your vehicle and then use that to guide your selections of parts.

    There are damned few good books out there - there's a Weber Tuning Manual; HP Books Weber Carburetors and the Haynes Weber Carburetor Manual. They are more theory than what I'd like, but they do provide a reference base.

    Please understand that Webers are special because there are just not that many installations (they are also fun :thumbup: ) but each installation is its own project, from getting the linkage to work acceptably to dialing in the right jets and correctors and emulsion tubes.... I can drive my car, but I am into my second year of this project to get it the way I want it.

    If you look up my picture here on the site, you'll see one on how close I am to my Webers.

    Good Luck.
     
  5. zrayr

    zrayr Well-Known Member

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    Sorry to hear about the blow-up. My first overhaul of 6s1117 original engine lasted a few months, at which time a cam lobe when flat. Luckily, the block was OK, and I only lost the cam, 2 valves, a roller rocker arm, a piston, 2 push rods, etc. Now going on 4 years on the subsequent rebuild

    I'd love to see a photo or two of your linkage. Can you post them or email (zrichter@austin.rr.com) ?

    What is the clearance like to the GT-350 hood ? Do you know if using the reverser plates add too much height for that style hood?


    thanks,

    Z. Ray
     

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