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Technical Tell me about the C3B or C3BX manifold

Discussion in 'Traditional Hot Rods' started by Greasyman, Jan 27, 2018.

  1. Greasyman
    Joined: Oct 23, 2010
    Posts: 139

    Greasyman
    Member

    Just bought one tonight without knowing much. A little research after I got home told me it was designed to be compatible with the old Holley 3 barrels, but it'll work fine with a 4 bbl. Anyone know the difference between the X and non-X? Anyone here ever run one?
    I bought it because it has the hole for the oil filler tube, and it was right there when I first looked at CL, like it was meant to be. Only $80, too.
    I decided I needed a manifold because I had removed the 4160 from the 283 in my T bucket, and I realized the manifold that was on there was an old spreadbore Streetmaster with some kind of four hole adapter with these angled holes for the primaries. I'll freely admit I don't really know what it is I was looking at, but it seemed sort of cobbled up (like most of the rest of the car), so I figured I'd just get a dual plane manifold meant for a squarebore.
    So will this be an improvement, or should I have just stuck with the Streetmaster? Is the adapter on there appropriate?
     
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  2. Deuces
    Joined: Nov 3, 2009
    Posts: 17,633

    Deuces
    Member
    from Michigan

    How about some pictures???
     
  3. arincee
    Joined: Dec 2, 2007
    Posts: 51

    arincee
    Member

    If you put a C3B and a C3BX side by side they look the same. Hot Rod Deluxe dyno tested several different intakes on a built 283 several years ago and the C3BX made a little more horsepower than the C3B. I've used quite a few of them over the years and they both work good. If the one you bought is in good condition with no cracks or stripped threads, you got a good deal.
     
  4. krgdowdall
    Joined: Apr 3, 2015
    Posts: 78

    krgdowdall
    Member
    from Alberta

    The C3B came out in 67 or 68 and was basically a copy of the Corvette L79 /Z28 manifold with the plenum divider notched to clear the Holley 3 bbl carbs. The C3BX is a newer version , introduces in 70 or 71 with a few modifications or improvements. I have a C3B but have seen a slightly different version of it. Mine has a oil fill tube angled to the pasenger side and a single square Holley carb pattern. I have seen a version that had the oil fill tube angled to the driver side and had a second set of carb bolt holes, for Holley/ AFB I believe. The C3BX has the mount for the choke heater element on the pasenger side. Good looking manifold , cant go wrong for $80
     
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  5. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 5,694

    56sedandelivery
    ALLIANCE MEMBER

    I always wondered IF the C3BX was made for the 461X double hump heads; they had slightly raised/enlarged runners, so a better fitting intake manifold would be of benefit. Just a thought. I am Butch/56sedandelivery.
     
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  6. 1934coupe
    Joined: Feb 22, 2007
    Posts: 3,368

    1934coupe
    Member

    I have had one CB3X for over 40 years, and put it on whatever engine I have in my 57 at the time. I love it.

    Pat
     
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  7. wayne-o
    Joined: Jan 22, 2006
    Posts: 266

    wayne-o
    Member

    I have run a C3B and 1403 Edelbrock on the 327 in my roadster for years. Great combo. I had an X also but never ran it.
     
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  8. belair
    Joined: Jul 10, 2006
    Posts: 8,057

    belair
    Member

    Brad54 may have done some comparisons on those. I have a c3b I bought in 76. First hot rod part I ever bought.
     
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  9. joel
    Joined: Oct 10, 2009
    Posts: 1,506

    joel
    ALLIANCE MEMBER

    You have one with out the plenum butchered and $80; you did great!


    Sent from my iPhone using H.A.M.B.
     
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  10. MIKE STEWART
    Joined: Aug 23, 2016
    Posts: 226

    MIKE STEWART

    I have a C3B bought off Ebay for $90 - great shape. I bought to install on a 327. It currently has the stock 4-jet small Rochester 4-V carb. I rebuilt it - not really happy with idle and performance. I plan to install the C3B and a Edlebrock 600 CFM elect. choke carb. On the do list - just not done yet. This 327 has the Dountov 30 / 30 solid lift cam and 2.5 Vette rams horn exhaust.
     
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  11. Dooley
    Joined: May 29, 2002
    Posts: 2,562

    Dooley
    Member
    from Buffalo NY

    my car had run a C3B since the early 70's... the plenum was milled down then though....they made them with oil fill to both sides, mine goes to the pass side. I changed it because I could not use the oil fill tube with my 350 as I had a PCV system so I filled the fill tube with a freeze plug.

    Brad54 did compare them a few years ago...

    I have mine for sale but I think I'll keep it for a 283 I have sitting around.
     
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  12. 29moonshine
    Joined: Dec 30, 2006
    Posts: 1,279

    29moonshine
    Member

    i thought the rear runner was different so you could use a hei dist on the c3bx
     
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  13. DDDenny
    Joined: Feb 6, 2015
    Posts: 12,069

    DDDenny
    Member
    from oregon

    Probably not important to most here but FYI, the 64/65 L/76 and L/79 style intake (GM) had the oil fill tube angled toward the passenger side and the 66/67 version toward the driver side. How this correlates to the Edelbrock intake I'm not sure.
     
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  14. Fordors
    Joined: Sep 22, 2016
    Posts: 2,090

    Fordors
    Member

    The 1965 C-4B pre-dated the C-3B by about four years. It differed from the early 340 and 350 horse SBC factory manifold with it’s gently radiused runners as compared to the square runners and 90* bends on the Chevy manifold.
    If anything it was the Chevy engineers that copied the Edelbrock design for the 1967 Z28 and eventually the LT-1.
    It was the 1969 introduction of the Holley 3 bbl. that called for the modification of the C-4B into the C-3B.
    1971 brought the C-3 BX and I don’t know but maybe the changes were to the size of the ports to better fit the taller ports on the 350.
     
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  15. henryj1951
    Joined: Sep 23, 2012
    Posts: 2,306

    henryj1951
    Member
    from USA

    Last edited: Jan 31, 2018
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  16. porknbeaner
    Joined: Sep 12, 2003
    Posts: 41,007

    porknbeaner
    Member

    There is something good that came out of the 3 bbl intakes that most guys don't seem to know.
    We used to ( actually I still do) cut a notch between the sides on intakes and called it a power notch. They only function when the rear barrels are open and it opens the intake up along the same lines as a 360 intake, so you get the low rpm grunt of a dual plane and the high rpm power of a 360 manifold.

    Just information and nothing more
    Carry on
     
  17. henryj1951
    Joined: Sep 23, 2012
    Posts: 2,306

    henryj1951
    Member
    from USA

    ^Correct as usual we ground out the center dividers also...
     
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  18. My C3BX, dual bolt pattern, no notch, fill tube angles to the drivers side, and no room for an HEI.
    c3bx.jpg
     
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  19. Dooley
    Joined: May 29, 2002
    Posts: 2,562

    Dooley
    Member
    from Buffalo NY

    This is what mine looks like 20180131_171008.jpg
     
  20. Fordors
    Joined: Sep 22, 2016
    Posts: 2,090

    Fordors
    Member

    I have a C-3BX on my sedan and IIRC correctly is has the four tapped holes and the notch in the plenum divider.It is interesting that yours does not have the notch, maybe there are more variations then we thought Rich. Thanks for posting that.
    Dooley, I am pretty certain that yours was modified at some point.
     
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  21. Dooley
    Joined: May 29, 2002
    Posts: 2,562

    Dooley
    Member
    from Buffalo NY

    It was
     
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  22. henryj1951
    Joined: Sep 23, 2012
    Posts: 2,306

    henryj1951
    Member
    from USA

  23. henryj1951
    Joined: Sep 23, 2012
    Posts: 2,306

    henryj1951
    Member
    from USA

    X- has dual bolt holes -n- NO cut in the center.
     
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  24. henryj1951
    Joined: Sep 23, 2012
    Posts: 2,306

    henryj1951
    Member
    from USA

    Note the flat heat riser pad in Rich B's pic ...
     
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  25. Dooley
    Joined: May 29, 2002
    Posts: 2,562

    Dooley
    Member
    from Buffalo NY


    Something like the RPM air gap has?
     
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  26. henryj1951
    Joined: Sep 23, 2012
    Posts: 2,306

    henryj1951
    Member
    from USA

    ^ yes or sometimes even more cut out of the center.
     
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  27. 1Nimrod
    Joined: Dec 11, 2018
    Posts: 121

    1Nimrod

    henryj1951;Sorry I know its an old post But...In Rich B pic of his C3BX notice that his upper runners are on opposite side. His upper runner's are on the "driver's side" it has no cut for 3bbl carb, has duel bolt pattern for carb, has mount for choke pull off, has a coil mount, and oil fill tube on driver side. My C3BX is almost like the C3B you posted henryj1951 but you have no coil mount, your oil fill tube is on the passenger side and your upper runner's are on the passenger side like my C3BX. I bought my C3BX off of a HAMB member. It has a coil mount and single bolt carb pattern,the oil fill tube is on the driver's side, it has no choke pad, my top runner's are on the passenger side like henryj1951 C3B upper runner's are, I have a "cut" in center from the factory like your C3B. I've noticed that there are C3BX's with upper runner's on both the driver's side and passengers sides. It's odd because the earlier C4B's had upper runner's only on driver's side with long upper runner in front and back. And C3B's I "think" have them just on the passenger side with the shorter front and back runner's. But Rich B's C3BX upper runner's are on the driver's side and has the long front and back runner's like the C4B. Please Look at the picture of my Eddy C3BX it's just the opposite of Rich B's C3BX. My C3BX does not have dual bolt pattern for the carb, but it does have a cut in center from the factory. Seems they did use for what ever reason the old mold like the C4B used on some C3BX with the upper runner's on the driver's side. The Eddy Co. made the C3B upper runner's on the passenger side (maybe only on that side cuz I have not seen any on the driver's side yet) The C3BX upper runner's are on "BOTH" the driver's side and passengers side's. Some members say they look like the Z/28 manifold and other members say no they don't. I think it's possible some have seen or owned the C3BX with the upper runner's on the passenger side like the Z/28 manifold have there's. (This is just my opinion) Possibly other members have owned or seen the C3BX (like Rich B's C3BX) that has the "Look" of the Old C4B with the upper runner's on the driver's side,they have the long runner's that are not as efficient like the C4B. The C3BX that looks like the Z28 manifold have the more even center upper runner's on the passenger side that are much more efficient. Like Fordors said there are many different variations of the "C3BX" and unless you look really close you won't notice the difference especially with the upper runner's being made on both sides, I'm not sure which type was made first the C3BX with the driver side upper runner's OR the C3BX with the passenger side runner's. Or maybe they made both style's at the same time ??. From 1Nimrod
     

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    Last edited: Mar 18, 2019
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  28. deathrowdave
    Joined: May 27, 2014
    Posts: 1,725

    deathrowdave
    ALLIANCE MEMBER
    from NKy

    Mine reads F4B , it looks completely different ! Sorry I couldn’t resist ! They are great intakes , no matter which one you have , I have used both in my Chebbie days . There is an F4B hangin in my garage now , I have been offered crazy money for , but there is also a matching set of correct era valve covers , just fun to look at and remember how many engines and cars I used them on .
     
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  29. Bullit68
    Joined: Sep 16, 2009
    Posts: 57

    Bullit68
    Member
    from Verona, PA

    I wanted an early intake with a fill tube and recently found a C3B on local CL. Paid $65 for it, and in good condition. Going on a 327, to look like an old 70’s build
     
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  30. 1Nimrod
    Joined: Dec 11, 2018
    Posts: 121

    1Nimrod

    deathrowdave; It would be cool to see the old C3BX in a dyno against the newer Eddys just to see how the old C3BX stacks up to the new and improved models.
     
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