BBC Build

Discussion in 'Engine Topic' started by Strange81Z, Apr 7, 2021.

  1. Strange81Z

    Strange81Z Veteran Member Lifetime Gold Member

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    OK guys, I decided I’m going with a BBC. So, since I have to build from ground up. Looking at things it seems the heads are the most expensive. Should I hunt a certain head and build around those heads? I don’t think finding a block will be a big issue but finding heads will be. Am I wrong?

    So what heads should I hunt for? I don’t want to pay $1K each for aftermarket heads.
     
    Last edited: Apr 7, 2021
  2. Jodi

    Jodi Veteran Member

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    The 781 or 049 casting #s are still plentiful and makes decent torque when prep correctly.
    Choose a piston that would yield 9.5 - 10.0 SCR with the 119cc combustion chamber.
     
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  3. G72Zed

    G72Zed Veteran Member

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    As Jodi states above, if you can find a good used complete set of 781 or 049, and your handy with a die grinder to clean up the bowls, you will be good. Having a "buddy" in the machining business would help too!!

    If your on a budget, but willing to spend the extra, the QualFast has a nice BBC Alum. head, 15-132722 for the Oval, and 15-133021 Rectangle ones, i got the Rec. port in full kit form. Very nice for the price point, would be more expensive getting a set of old Irons up to snuff, and they would not flow as well.

    And up here, if you got some old 781/049's, by the time you buy all new parts, add in some porting and the machining costs, your $$ ahead with these QualFast castings, and they are aluminum to boot.

    At least it's food for thought for ya.
     
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  4. 1980RS

    1980RS Veteran Member

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    Depends on what you are going to use the car for. In the last few years I have run3 sets of heads, 236 peanut port heads
    $25 for heads
    $85 for new valves
    $35 for retainers
    $75 for springs and keepers
    $13 for seals
    I did a mild port job and 3 angle valve job. Best time with those heads, 11.70'[email protected]

    2nd set, 360 casting peanut port heads bought at the swap meet $250 with all super good parts except for junk valve springs
    Best time after I ported these [email protected]

    Aftermarket heads are great but the only cast iron ovals I think that are out there are Merlins and they are pricey. AFR's are fantastic but are huge money, Trick flows are good as well as Brodix. As for Edelbrock heads, me personally would never buy anything new from them again. Like I said 500hp out of any truck 454 is pretty easy hp IMO. Like others say the 049 and 781's are the best factory ovals out there.
     
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  5. Strange81Z

    Strange81Z Veteran Member Lifetime Gold Member

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    So what is the difference between oval and rectangle performance wise? This will be my first engine build so I’ll be asking basic questions like this.
     
  6. carhead22000

    carhead22000 oldblue

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    ovals use a lower rpm range for power.rectangle use more rpm.imo ovals are the way to go for a street car.i like keeping my rpms low.
     
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  7. G72Zed

    G72Zed Veteran Member

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    Well, basically to use GM as an example, the small oval ports (aka peanut ports) were used on large trucks/bus HD applications for there low RPM TQ and came on 366/427/454 if my memory serves me well. Now, a good porter that knows what to do, can get those "peanut"ports to work very-very well, look @ 1980RS on this site.

    GM's next step up was the (larger or regular) Oval ports, used on 396/427/454 and was the "mid" HP head and was complimented with a Hyd. cam in most cases.

    GM's full effort was the Rectangle port, used in the highest HP/RPM applications in 396/427/454's, and was complimented with solid lifter cams in most cases due to higher RPM ranges. To be fair, the Rectangle ports on a 396 was a bit of a mis match, the 427 took advantage of it's larger bore, but had the RPM potential of it's borrowed 396 crank. The 454 was everything, TQ and HP.

    The most important thing is the heads port volume/shape/velocity/CFM(notice CFM is last) has to match the cubic inch and target HP-RPM needs or requirements and compliment the other components. There is nothing more disappointing than someone buying "too much" cylinder head for the application and engine/car parts combination and then it fails to make the power, tq, and has a narrow power band that it fails on most levels of measurement, and had overall bad manners.

    So I will ask, what are your needs or expectations for power & rpm wise, fuel type, maintenance schedule,street manners, longevity, and most of all....budget. This will dictate the build approach generally speaking.

    Hope this helps out.
     
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  8. Strange81Z

    Strange81Z Veteran Member Lifetime Gold Member

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    My goal is the have a street car that might do test and tune nights at the track. I’ve never hit the track. All of my racing was always 1/4 mile runs on an old country road. That’s the limit of my drag racing experience. So I what it to be a series street machine.

    Budget isn’t too much of a concern. I just want a solid motor with enough HP to keep me happy for while. I’m a cheap MoFo so when I see the heads for 2K each I’m like, it’s not going to happen.

    if I had to throw a $$$ for budget I’d say 5K for the motor build. I’m not sure what that’s get me. I want to build the motor myself (with my son) so I don’t want a crate motor. I want to get a block and heads and get all of the machine work done then my son and will will build the motor.
     
  9. Strange81Z

    Strange81Z Veteran Member Lifetime Gold Member

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    Awesome response man! Thank for the education.
     
  10. G72Zed

    G72Zed Veteran Member

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    Well, if this is going to be a BIY project with your son, I would suggest seeking out, and working with a good reputable engine/machine shop in your area and get a complete detailed estimate done on all the machine work & services required for a full rebuild of all major components.

    Many times they have a "check list" of services and costs to give you an idea what your getting into.

    Then a complete parts list & build plan can be started to see what's needed based on your expectations and budget.

    From that parts list, you go hunting for the best deals and what fit's your needs. There will always be good deals like what 1980RS mentioned, but you can't budget on that for the regular build as those are one off deals and may not be there at the time.

    Based on the local machine shop labour rates, and actually building & planning this on paper first, you may find out how much of a good deal a "crate" engine is, and why they are so popular.

    In most cases, a one off, boutique full rebuild of a certain engine due to rarity or # matching comes up more in costs vs a "crate". But, it's not as fun or satisfying as building it yourself. I'm building a BBC for a customer now, the complete build plan has been laid out and agreed to by customer before anything is started.

    Good luck in you build.
     
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