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  1. #11

    Re: cracked heads on a 426

    Larger valves will not hurt. The chamber size and piston top clearance are the concerns.
    I'm not a Mopar guy so I'm not sure; Will the intake manifold fit the different heads?
    Last edited by Captain Ralph; 09-26-2021 at 05:24 PM.

  2. #12

    Re: cracked heads on a 426

    Hi Akin,

    In a broad sense, Chrysler made two blocks: the small block "A" block, and the larger "B" block.
    The A has the distributor in the back mounted vertically, and the B has it in the front at an angle.

    Later the B block (now obsolete) was supplanted with one with longer cylinders, the so-called "Raised B" which is what RB stands for.

    It is used in the 383, 400, 413, 426 (Hemi and wedge), and 440 (I know little about the early 330, 350, or 361).

    (The early A block similarly evolved into the "LA" is 273, 318, 340, and late generation 360.)

    > Akin said:
    > 1964-1967, 361/383 B/RB-series big-block, 2.08/1.60 valves, 73.5cc (not a wedge!)

    In Chrysler nomenclature, everything *but* the Hemi or early polysphere (Red Ram) is considered a wedge.

    I am not at all surprised they used that casting since as far as I know they are fully interchangeable and may just be what was on the assembly line.

    The Max Wedge is a pretty special racing engine and *extremely unlikely* to be in your Hatteras.
    https://en.wikipedia.org/wiki/Chrysler_B_engine

    I used to drive a 426 Hemi with a RB and cross-bolted mains. It may be that the casting you have is two/four bolt (which I think some are) but since the year is right, I think it is original and not a concern.

    DAN
    Last edited by drburke; 09-27-2021 at 02:58 PM.

  3. #13

    Re: cracked heads on a 426

    Hi Akin,

    > Why is my casting for a 361/383 block, when the engine is a 426 RB?
    Because the 361 and 383 are also RBs which is fine

    >Is it possible that the prev owner put something different than the original?
    Possible but he would have had to blow up the original engines within the first year to have picked up 1964 castings, so doubtful.

    >The better fit would be: 2406518 – 1964, 426 B/RB-series big-block, 2.08/1.88 valves, Max Wedge, 86cc. Should I get this instead of what I have there now?
    No, I think what you have is the original and fine.

    ======
    Regarding new head choice, as I said earlier the alloy heads do run cooler which helps avoid predetonation especially on a non-computer-controlled engine. (BTW, I think any cast iron head 383, 400, 413, 440 will work if you go that route, but really the new after-market heads are much better.)
    Always possible to have corrosion issues as mentioned; just keep an eye on them. That said, a raw water cooled engine is more likely to be too cold so that benefit may not be realized.

    But use good head gaskets to prevent differential expansion/contraction issues.
    https://www.cometic.com/applications...e--426ci70l-v8
    (The Cometic MLX use stainless shim layers which would be good for a raw water engine.)
    Also, while you are in there, change over to ARP studs for the same reason.
    https://arp-bolts.com/kits/arpkit-de...p?RecordID=459
    (Using head studs instead of head bolts improves the clamping load.)

    The new aluminum heads seem to have bigger intakes, which is okay for wide open operation but slightly less torque (potentially) depending upon your intake.

    The slightly smaller exhausts don't bother me; there have been enormous strides in flow simulation and clearly the alloy engineers have something in mind--I bet they flow significantly better than the original cast items.

    The combustion chambers should definitely be the larger ones, which is a significant concern. Your engine will operate in a high-output low speed regime almost all of the time. The older 73 cc heads theoretically deliver better compression and performance in general, but our fuel octane is *much* worst (lower) than when those engines were designed so you are far better off with the 84-85 cc ones for longevity.

    DAN
    Last edited by drburke; 09-27-2021 at 04:01 PM.

  4. #14

    Re: cracked heads on a 426

    Quote Originally Posted by drburke View Post
    Hi Akin,
    >The better fit would be: 2406518 1964, 426 B/RB-series big-block, 2.08/1.88 valves, Max Wedge, 86cc. Should I get this instead of what I have there now?
    No, I think what you have is the original and fine.
    combustion chambers should definitely be the larger ones, which is a significant concern. Your engine will operate in a high-output low speed regime almost all of the time. The older 73 cc heads theoretically deliver better compression and performance in general, but our fuel octane is *much* worst (lower) than when those engines were designed so you are far better off with the 84-85 cc ones for longevity.
    ...
    DAN
    Dan,
    So, I looked at heads for 383 vs the 426 blocks, and you are right, the same heads fit both blocks, so the difference is CC, and valve sizes. This is the head that is closest to my current cc:
    Edelbrock 5090.
    https://www.autozone.com/engine/perf...090/300702_0_0

    It has slightly larger exhaust valves, - do you think it will be ok?
    2.14"/1.81 vs 2.08/1.60

    Regarding the head gasket, with raw engines running cooler, do I really need the multi layer (5 weeks to produce) or can I use the stainless marine gaskets I already have at hand?
    Akin Tosyali
    Hatteras 41 -Barbaros

    Chicago

    Barbaros, Hatteras 41' Before and after restoration

  5. #15

    Re: cracked heads on a 426

    Hi Akin,

    I think for this application (vs some all-out performance balance thing) the new valve sizes are fine in my opinion.

    And sure, use the SS gaskets you already have.

    Previous commenters are correct about the raw water engine being cool, so I may be imagining a solution to a problem you don't have :-)

    Looks like you are getting close to a solution, but I am no expert so get lots of confirmation checks from the manufacturers.

    A little less compression from the 84cc head may be a good idea for low octane pump gas, but see what Edelbrock says...

    DAN

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