BBC carburetor choice
+ Reply to Thread
Results 1 to 13 of 13

Thread:
BBC carburetor choice

  1. #1
    Senior Member
    Join Date
    Aug 2008
    Posts
    357

    Default BBC carburetor choice

    I'm sure this topic has been beaten to death then revived and beaten again. I have a BBC 476, aluminum oval port heads,roller cam .580 lift, dual plane intake, 9-1 compression, center rise exhaust. I'm getting rid of my 830, putting on a marine carb. I'm also switching to an AA impeller, trying to keep rpm's at 5000 or lower.

    Choices: I have a reman.750 Holley dp marine sitting in the garage, run it as is and jet accordingly. OR have that carburetor rebuilt by the carb shop to get everything out of it possible. OR get a brand new 850 quick fuel, they seem to be the best brand new choice for a marine carburetor.

    opinions?

  2. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  3. #2
    Village Idiot fc-Pilot's Avatar
    Join Date
    Jan 2008
    Location
    Peoria, AZ
    Posts
    3,277

    Default

    Quote Originally Posted by nos1967 View Post
    I'm sure this topic has been beaten to death then revived and beaten again. I have a BBC 476, aluminum oval port heads,roller cam .580 lift, dual plane intake, 9-1 compression, center rise exhaust. I'm getting rid of my 830, putting on a marine carb. I'm also switching to an AA impeller, trying to keep rpm's at 5000 or lower.

    Choices: I have a reman.750 Holley dp marine sitting in the garage, run it as is and jet accordingly. OR have that carburetor rebuilt by the carb shop to get everything out of it possible. OR get a brand new 850 quick fuel, they seem to be the best brand new choice for a marine carburetor.

    opinions?
    OK, I will throw my two cents in. Your combo will run best with an 850 if you are trying to get that last 3-4 MPH out of it. I would be willing to bet (all else being equal) that the 750 would be very nice and drivable and would perform very well. For many basic hopped-up BBC that is not too racey I often will throw on a 750 vacuum secondary as they perform well and are also easy to tune. If you are good with tuning carbs then the 850 DP will get you that last bit.

    Paul

  4. #3
    Senior Member
    Join Date
    Aug 2008
    Posts
    357

    Default

    Thank you. I'm having the 750 rebuilt to my engines specs.

  5. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  6. #4
    Some guy obnoxious001's Avatar
    Join Date
    Dec 2007
    Posts
    3,570

    Default

    Quote Originally Posted by fc-Pilot View Post
    OK, I will throw my two cents in. Your combo will run best with an 850 if you are trying to get that last 3-4 MPH out of it. I would be willing to bet (all else being equal) that the 750 would be very nice and drivable and would perform very well. For many basic hopped-up BBC that is not too racey I often will throw on a 750 vacuum secondary as they perform well and are also easy to tune. If you are good with tuning carbs then the 850 DP will get you that last bit.

    Paul

    I just noticed this, and particularly the 5000 rpm part. Basic calculations show that even if that engine was running 100% volumetric efficiency, the demand should be around 688 CFM at 5000 rpm.


    On the practical side, many years ago I rebuilt a "stock" 454 in a jet boat. The block was zero decked to gain a bit of compression with the stock, standard bore pistons, and a jet boat cam installed. The engine and come with a 715cfm Holley, and so we ran that, and actually surprised many 18 foot jets with headers, beating them with a 20' open bow, covered engine Bahner. Well, one day the owner figured he would buy a new 850 carb and go faster, and even with some jet changes and tuning, it never did exceed what the engine would do with the "little" 715 cfm carb.

  7. #5
    Senior Member ol guy's Avatar
    Join Date
    Mar 2008
    Location
    Lake Elsinore Ca
    Posts
    3,812

    Default

    Quote Originally Posted by obnoxious001 View Post
    I just noticed this, and particularly the 5000 rpm part. Basic calculations show that even if that engine was running 100% volumetric efficiency, the demand should be around 688 CFM at 5000 rpm.


    On the practical side, many years ago I rebuilt a "stock" 454 in a jet boat. The block was zero decked to gain a bit of compression with the stock, standard bore pistons, and a jet boat cam installed. The engine and come with a 715cfm Holley, and so we ran that, and actually surprised many 18 foot jets with headers, beating them with a 20' open bow, covered engine Bahner. Well, one day the owner figured he would buy a new 850 carb and go faster, and even with some jet changes and tuning, it never did exceed what the engine would do with the "little" 715 cfm carb.
    I agree with ob 1. My o2 run the 750 and jet accordingly. Reason being that I have played with many carbs and the school of thought is bigger is better. WRONG. On a jet boat you are not getting to RPM that would require an 850. If I had my choice in your'e boat I would stay with the 4779(750) carb and tune to work. I have an 850 dp on my cruiser and it is rolling over at wot. reason being OVER-CARBED. I would rather it lay down (starving for fuel) than waste gas over feeding it. FWIW I am pulling the 4781(850) carb off and putting the 3310-2(750 Vac sacondary) on. Info 461 bbc oval port 9:5 single plan manifold. MLAO. Mark

  8. #6
    Village Idiot fc-Pilot's Avatar
    Join Date
    Jan 2008
    Location
    Peoria, AZ
    Posts
    3,277

    Default

    great points these guys brought up. One other thing I did not think of was what dual plane intake? If it is completely divided then getting away with the bigger carb would be easier, but if you had an open spacer, or the divider was cut down then I would definitely go with the 750. I am convinced the 750 vacuum secondary carb is the most universal and easy to use carb for performance use of all the holleys. They don't have to be right on to work well.

    Our old family v-drive with a warmed over BBC had an old 750 VS on it and it just worked. We knew little at the time about holley tuning and it just worked for years and years and years and... You get my point.

    Paul

  9. #7
    Senior Member f_inscreenname's Avatar
    Join Date
    Dec 2007
    Location
    Pasadena, Maryland
    Posts
    1,527

    Default

    For that motor I would think anything more then a 750 and you will be burning extra gas for nothing but wet plugs. If you want a set and forget carb you can not beat the Edelbrock 750 - 1410 marine carb.
    A winner is just a loser that got up and did it one more time.
    1959 Biesemeyer - 4pt Hydro Drag - 2013 ACBS Winner - Best Race Boat
    1966 Donzi 16
    1967 Nova Marine - SuperNova24 - ACBS Winner - 2012 Best Race Boat - 2016 Peoples Choice & Best Non Wood
    1972 John Allmand - Nova 19
    1982 PolarKraft -Jonboat - Crab Killer

  10. #8
    Senior Member
    Join Date
    Aug 2008
    Posts
    357

    Default

    I'm sticking with the 750 Holley and got a wideband o2 setup to monitor a/f and tune the carb.

  11. #9
    Senior Member Mash on It's Avatar
    Join Date
    Mar 2008
    Location
    Willow Beach & BHC
    Posts
    170

    Default

    Quote Originally Posted by nos1967 View Post
    I'm sure this topic has been beaten to death then revived and beaten again. I have a BBC 476, aluminum oval port heads,roller cam .580 lift, dual plane intake, 9-1 compression, center rise exhaust. I'm getting rid of my 830, putting on a marine carb. I'm also switching to an AA impeller, trying to keep rpm's at 5000 or lower.

    Choices: I have a reman.750 Holley dp marine sitting in the garage, run it as is and jet accordingly. OR have that carburetor rebuilt by the carb shop to get everything out of it possible. OR get a brand new 850 quick fuel, they seem to be the best brand new choice for a marine carburetor.

    opinions?
    461 BBC. 750 Holley, Vacuum secondaries (3310) Vic Jr. air gap. AA American Turbine Impeller, (larger than a Berk 2A) Oval port heads, 9.0:1. .578"/.578", 228/232* @ .050". Logs and snails. 4950 to 5K. all day. everyday. Family boat.

    Dan'l
    "Never mind the mule, Just load the wagon"
    '76 Eliminator 21'

  12. #10
    Senior Member
    Join Date
    Aug 2008
    Posts
    357

    Default

    Setup is very close to mine. I have oval port pro comp aluminum heads, so who knows how they actually flow. .580 lift roller cam, 9-1, dual plane air gap intake. Just switched to center rise manifolds, and switched to a MPD detailed aggressor Bronze A+ which I was told will spin like a Berkeley 2A+. Out of the box Holley marine 750, will see if any jetting needs to be done. Was spinning a fresh MPD built pump with A- berk impeller 5200rpm with the 830cfm I got rid of. Changing carburetor, bigger impeller, much better exhaust. Curious to see how things go.
    Last edited by nos1967; 05-11-2017 at 06:06 AM.

  13. #11
    Senior Member
    Join Date
    Mar 2017
    Posts
    113

    Default

    a stock 330 horse 454 comes with a 800 cfm q-jet carb,imo the quickfuel 850 is the right way to go.

  14. #12
    Old Timer LeE ss13's Avatar
    Join Date
    Dec 2007
    Location
    San Dimas CA
    Posts
    1,119

    Default

    Quote Originally Posted by nos1967 View Post
    I'm getting rid of my 830, putting on a marine carb.
    What ya gonna do with the 830? Is it for sale? If so, what is the LIST number?
    I don't know what I don't know because I forgot !!!

    Quote Originally Posted by Freedom Child View Post
    They all look alike upside down
    Quote Originally Posted by Wannabe View Post
    A grace of the English language that you obtain simply supersedes all reasonable expectations.

  15. #13
    Senior Member
    Join Date
    Aug 2008
    Posts
    357

    Default

    Already sold on eBay, had it up for sale on here and Facebook for a while with no bites. Was 80511

+ Reply to Thread

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Please select your insurance company (Optional)

Log-in


Tags for this Thread

Digg This Thread

Posting Permissions

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
  •  
 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95