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Hot Rods Man-A-Fre Fuel Induction

Discussion in 'The Hokey Ass Message Board' started by MR MOPAR, Jan 16, 2020.

  1. MR MOPAR
    Joined: Jun 7, 2011
    Posts: 116

    MR MOPAR
    Member
    from california

    Couple articles have explained this part.

    Made for Chevrolet 265 and 283.

    1 Four big Rochester 2 barrels as close to ports as you can get.

    2 Nozzle for each carb and pair of ports in Man-A-Fre 'manifold'.

    Okay.Here is the question.

    What is the rest of the system?

    Between fuel tank and nozzles.

    All articles I have seen go into all kinds of detail about these items and then zippo nada

    nothing about plumbing and fuel pump.

    Thanks.
     
  2. dirty old man
    Joined: Feb 2, 2008
    Posts: 8,339

    dirty old man
    ALLIANCE MEMBER

    I've never seen one in person, but I'm thinking it only has to have a fuel pump, etc. like any carbureted setup. Have been told by others that they're sorta finicky about how they're tuned and adjusted.
    Back when I first started dirt oval racing, the limited sportsman class required a 2 barrel carb. and I ordered one from the same company and it ran great. Seat of the pants and lap times it seemed to out do the Holley 500 cfm 2bbl.when it came out.
    For the life of me, I can't remember the name of the guy who developed the stuff this company built and sold. I do remember he came from the Atlanta. GA area and later moved to CA.
     
  3. Mike VV
    Joined: Sep 28, 2010
    Posts: 1,686

    Mike VV
    Member
    from SoCal

    It's just four simple Rochester carburetors on a "plate".
    One carburetor feeds two cylinders, with a 1/2 square tube cast in to connect all four carburetor mounting base to help smooth the idle.
    There were at least two different sized carburetors used. The smaller (small Chevy) ones for the small engines, and the larger Pontiac carburetors for the big inch engines. The larger Pontiac carburetors may have been a bit too much for the small engines. Plus, as I recall, the bolt patterns were different.

    The carburetors all opened and closed at the same time, as each carburetor...fed two cylinders, and they all need fuel and air at the same time. So the linkage had to be rock solid to open all four, equally, at the "same" time.
    A stock fuel pump was plenty to feed all four. I drag raced mine in a full sized car (331 and 350 inch engines) and never had fuel problems. I never did use a pressure gauge, so I can't testify as to how close I was to running out of fuel at the end of the track. Never had notable fuel problems, at 6200/6500 rpm.
    I also drove mine daily, on the street for about four or so years (my only car).

    The blocks (under each carburetor) on the plate that were for an injection system (for nitrous oxide, alcohol) came undrilled. That was left for the customer to do.

    Early on, the plates (NOT manifolds !) were made for small and big Chevrolets, small Fords and Pontiac's. They could have been, but I don't recall one for any big Fords. Later there were Volkswagen, and other kits made.
    He also made up instructions to enlarge any of the Rochester carb. bodies (venturies).
    This actually worked, as I did modify one. I did a couple of things slightly different, but in general it did work to some extent.

    Harold Graves was the designers name. I spoke with him a couple of times. Very nice guy.

    Any other questions ?

    Mike

    P.s. - Tuning was mentioned.
    Yes, tuning took a little different thinking. They were NOT finicky as some say...if you know the little secrets. They did NOT take constant management to keep them running. Yes, they did, on occasion, require small adjustments, but this was was not daily, weekly, monthly as some would have you believe. I don't recall the details now, but every now and again, something would go on that would tell me to mess with them some. But again, this was more like a "yearly" thing, not very often.
     
    Last edited: Jan 16, 2020
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  4. Back in the 80s I had a setup for a SBF I was going to put on my coupe but never did. As I recall, its just like any other 4 carb setup as far as fuel lines. Mine had small holes connecting the ports in the manifold so that there was some type of plenum effect.
     
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  5. Moriarity
    Joined: Apr 11, 2001
    Posts: 15,771

    Moriarity
    SUPER MODERATOR
    Staff Member

    I have one on my corvette. Runs beautifully

    E76E46B9-D575-464B-8819-C673C03E7FFB.jpeg 7A657EAF-9DE8-4425-B778-09C22C90C25B.jpeg 44AB6F49-C545-4108-AE2D-E83B4977DEDE.jpeg
     
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  6. Moriarity
    Joined: Apr 11, 2001
    Posts: 15,771

    Moriarity
    SUPER MODERATOR
    Staff Member

    I think you may be referring to the "afterburner" option. It was Rochester fuel injection nozzles in the manifold under each carb. they were fed with fuel through a solenoid valve that was actuated only at wide open throttle. It was fed with the same fuel pump that fed the carbs. I think the idea was that they thought the system ran lean at WOT and needed more fuel
     
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  7. Mike VV
    Joined: Sep 28, 2010
    Posts: 1,686

    Mike VV
    Member
    from SoCal

    As noted, mine never needed more fuel, even on a 350 Chevy at 6200 rpm.
    Just proper jetting, just like any other carburetor would require.
    The connector as 56don notes, was NOT for a plenum effect. It was to smooth the idle.

    As I noted, as I was told by Mr. Graves, a non-gasoline (Nitrous Oxide, or alcohol) power adder location.

    Mike
     
  8. Speed Gems
    Joined: Jul 17, 2012
    Posts: 2,476

    Speed Gems
    Member

    @MR MOPAR This should answer your questions. Scan0001.jpg Scan0004.jpg Scan0016.jpg Scan0017.jpg Scan0018.jpg
     
  9. I stand corrected. Actually, that was what I was trying to describe, smoothing the idle.
     
  10. MR MOPAR
    Joined: Jun 7, 2011
    Posts: 116

    MR MOPAR
    Member
    from california

    Thank you for all the responses!

    Yes.Question has been answered.

    I dub these officially 'Man-A-Fre Adapter Plates'.Like it says in article.Plus respect for the inventor.Who wanted it to be 'manifold free'.

    Everybody that thinks they would sell like hotcakes at Speedway Motors for $229 raise

    there hand!

    Apparently the stock fuel pump will do it! Second to last page of article.

    Let me toss in Holley 2100's two barrels are plentiful or were.

    Might be easier to find than those Rochecter's.Don't know really.

    System was designed for the Rochester's.Don't know if it makes much difference.
     
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  11. PackardV8
    Joined: Jun 7, 2007
    Posts: 872

    PackardV8
    Member

    For nearly sixty years it's bothered me the carbs sit the wrong way round. If Graves really wanted to do away with the intake as much as possible, the obvious answer was to turn the four Rocks sideways and put one throat directly over each intake port.

    When I saw the introductory article in Hot Rod, back when long distance calls cost real money, I phoned him and asked that question. His answer, "You're right; sideways would work better. We decided to do it the 'wrong' way because the linkage is easier and it looks 'right' to those who don't understand function; most buyers aren't ready to understand or accept sideways carbs."

    jack vines
     
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  12. mgtstumpy
    Joined: Jul 20, 2006
    Posts: 7,722

    mgtstumpy
    Member

    user83810_pic287081_1303959595.jpg user83810_pic287082_1303959595.jpg
    Man-A-Fre.jpg
    Manafre decal.jpg
     
    Last edited: Jan 16, 2020
  13. Almostdone
    Joined: Dec 19, 2019
    Posts: 67

    Almostdone
    Member

    Great response Speed Gems. That was a nice article. Been to St Cloud many times.
     
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  14. We should have known that Mark would have at least 1 whether it was on a car or not. LOL When you look at the size of a 2gc, you can see several reasons they weren't turned sideways for port alignment. I read all the mag articles when I was young but the attraction wasn't strong enough to own one. It's nice to hear from owners 60 years after introduction. :)
     
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  15. MR MOPAR
    Joined: Jun 7, 2011
    Posts: 116

    MR MOPAR
    Member
    from california

    'Any other questions ?'

    1 This is REALLY the 4 carbs set on the ports only? No injectors? Can be run that way? On that Corvette I am not seeing the fuel block for the injectors.

    The 'Afterburner' was the setup to add 4 injectors?

    From the article you turn the injectors on at 4000 rpm.

    If so.I have seen injectors 'added' to carb setups to kick in at high rpm's.

    Also.We came up with 4 two barrels right on ports for Ford OHV V8 (Y block) a long

    time ago on our own.

    First time I took intake manifold off of my little 292 I go 'That head was made for 4 two

    barrels!'

    If Man-A-Fre with injectors is the 'Afterburner' option then it is all cleared up.
     
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  16. Moriarity
    Joined: Apr 11, 2001
    Posts: 15,771

    Moriarity
    SUPER MODERATOR
    Staff Member


    correct, my corvette does not have the afterburner injectors. they were optional. I previously had a big block setup that had the afterburners. It added 2 injectors under each carb that had a solenoid valve actuated by the gas pedal and when open it flowed additional gasoline (see inst sheet posted above) to the injectors
     
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  17. dirty old man
    Joined: Feb 2, 2008
    Posts: 8,339

    dirty old man
    ALLIANCE MEMBER

    Just went back and reviewed my post and I failed to note that Graves (thx for refreshing my memory on his name) modified that Pontiac 2GC so that instead of 2 venturi, there was one big oval hole! My crew and I had a drill of things to do in the event of a protest:
    (1)drain water and while it's cooling pull header and hold it up and yell "Here's the speed secret, 'headers by Dave'"
    (2) pull air cleaner and stuff rag into top of carb "to keep stuff from falling in it" disconnect fuel line and throttle linkage and remove intake manifold with carb attached and hold it up high, saying "yall see, it's a 2 bbl" then set it inside car and cover with large rag.
    (3) pull valve cover and head for bore and stroke measurement while making wisecracks about "Gotta figger out how to put zippers on this damn engine."
     
  18. MR MOPAR
    Joined: Jun 7, 2011
    Posts: 116

    MR MOPAR
    Member
    from california

    Thank you Moriarty

    'they were optional'

    Very hard to tell from most articles about Man-A-Fre setup.

    All cleared up!
     
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