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Crossfire / carb changeover update

Discussion in 'The Hokey Ass Message Board' started by JOECOOL, Jun 6, 2008.

  1. JOECOOL
    Joined: Jan 13, 2004
    Posts: 2,759

    JOECOOL
    Member

    About 6 months ago There was some posts on whether the 80's Chevy crossfire injection manifolds would work with carbs or not. I have just completed mine and have some info and pics. First of all let me say I am the cheapest ,low buck guy you probably have ever seen and the crossfire manifold was given to me with the warning,"you'll never get that thing to work right",Some of the things could be made better buy spending more money.
    Total spent was $58, carbs $5 each ,kits $10.40 each, the rest was aircleaners ,gaskets and nuts and bolts,oh, fuel line and fittings.It was installed on a 130,000 305 that despite the miles didn't use oil and ran very well.
    The plate for the top was a scrap peice of 1/4 aluminum ( we use this for motor plates for the drag cars we build) The HIE ignition just barely clears but it does clear. The carbs are Rotten chester 's off of mid 50's Pontiac.
    The carbs could be installed offset like the crossfire but the linkage would be more difficult to fab. The original crossfire aircleaner could be used if it was desired.Two AFB's was tried on the plate and will fit in an offset crossram type pattern but Once again the linkage would be tough and I certainly didn't need the CFM.
    These were front inlet carbs but plenty of room for fittings. I was not able to fit 3 two barrell carbs on this plate in any positions,unless the end carbs would be phony and hang over the lower part of the intake.
    Now for the good stuff ,it starts fine (no chokes) and runs as well as it did with the Q-jet. I have no idea what fuel mileage was before and still don't know. The carbs are not hooked up progressive ,both use idle circuts and both open at the same time. NO hesitation noted except when cold. A small block off plate was installed on the EGR valve mounting surface and was tapped for a fitting and a hose to the pvc in the valve cover. NOTE I blocked off all crossover exhaust in the manifold. This is required if you are going to use this pvc fix.
    In my opinion this is not a performance upgrade ,not a traditional piece,just a fairly inexpensive conversation piece.
    Best of luck!

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  2. JOECOOL
    Joined: Jan 13, 2004
    Posts: 2,759

    JOECOOL
    Member

    Yeah I know ,my photo skills suck ,I'll try to get some of the linkage side and post later.
     
  3. Nice job. I've always wonderd how that manifold would work with carburators.
     
  4. JOECOOL
    Joined: Jan 13, 2004
    Posts: 2,759

    JOECOOL
    Member

    more pics added first is of linkage and second is PVC valve setup.[​IMG] [​IMG]
     

  5. Neighborwood
    Joined: Nov 7, 2010
    Posts: 37

    Neighborwood
    Member

     
  6. Neighborwood
    Joined: Nov 7, 2010
    Posts: 37

    Neighborwood
    Member

    I picked up a crossfire manifold for $30.00, couldn't pass it by. Cut out the EGR ducting inside, evened the port runners, and finally opened up the runner outlets where they meet the head. Inside I placed baffles to direct the gas flow from each carburetor to its side. The baffle is difficult to match to the manifold interior. Then J-B welded the baffling to the manifold floor. Have to be careful the floor of the manifold is the hot water manifold heater. Next the EGR port became the PVC port with an interior opening in each of the baffles so each side gets its share.
    The engine is a 305 I used 2 Weber 32/36 carbs. ( because they were on the shelf) Used J-B weld to fill in some of the original manifold plate. and raised the bases with 1" of Mylar.
    Their air flow is some where between 120 to 150 CFM. So a good match.
    The 305 is in a 1500# roadster. Don't need more power. It starts and runs with no choke. The fuel and air jets in the carburetors is as supplied, haven't had time to do any jet tuning.
    Ask any questions.
     
  7. JOECOOL
    Joined: Jan 13, 2004
    Posts: 2,759

    JOECOOL
    Member

    Wow i was surprised to see this again . thanks for the memories
     

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