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Thread: How big of a carb????

  1. #1
    Senior Member MASTER BUILDER
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    How big of a carb????

    Hi I'm new to racing junk and am putting together a 70 chevelle with a smallblock and a muncie with 3.73 gears. The specs on the engine are (350 .60 over, edelbrock performer RPM heads, isky cam 505 lift 292 duration, 244 duration at .050. It has good headers,free flowing exhaust. I ran this combo with a 600 edelbrock carb and have been thinking of switching to a holley. I feel that the quadrajunk style carb is holding it back?? Any and all info is appreciated! THANKS WHITEY.

  2. #2
    Senior Member RACING JUNKIE
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    650 or 750

  3. #3
    Senior Member MASTER BUILDER
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    That really doesnt answer my question todd. I was looking at both 650 and 750. Which one will work best for my setup??

  4. #4
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    I had a 72 Chevelle with a 355 that had about the same setup and I ran a 750 dp with the jets that came in it and it worked great. My cam was a little bigger but only like 520 lift with a 302 duration(somewhere in that range). I also drove mine alot on the street and never had any problems loading up.
    Wasn't me.

  5. #5
    Senior Member RACING JUNKIE
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    Quote Originally Posted by whitey70ss
    That really doesnt answer my question todd. I was looking at both 650 and 750. Which one will work best for my setup??
    If it's a street car I would go with the 650. It will be more responsive and fun to drive. I had a 400 with a cam very similar and I went from a 750 to a 650 and it was way more peppy to drive,.

  6. #6
    Senior Member MASTER BUILDER
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    Ok thats the info Im looking for. If I go with A 750 cant I jet it down a little to get that responsivness??

  7. #7
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    IMO if you go from a 750 to a 650 and it makes it more peppy than the 750 was just to much. Since it worked for TOD it may work for you. I had tried a 650 on mine and the 750 was alot more responsive. It all depends on what your engine likes. If you have access(friends etc) to one of each, try them and see which one works better. I may have had more compression and more flow than what you have.

    By the way TOD, I like the avatar.
    Wasn't me.

  8. #8
    Senior Member RACING JUNKIE
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    Quote Originally Posted by chrisr
    IMO if you go from a 750 to a 650 and it makes it more peppy than the 750 was just to much. Since it worked for TOD it may work for you. I had tried a 650 on mine and the 750 was alot more responsive. It all depends on what your engine likes. If you have access(friends etc) to one of each, try them and see which one works better. I may have had more compression and more flow than what you have.

    By the way TOD, I like the avatar.
    WHAT HE SAID . Always better to test before you buy if you can.

    And yes the reason the 650 was better for me was the 750 was just too big.It was a 9:1 motor and the 750nhad the 50 cc pump on the rear and it just would fall on it's face when you floored it...the 650 brought it to life.

  9. #9
    Senior Member RACING JUNKIE jmarksdragster's Avatar
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    A 750 vacuum would work great, best of both worlds. Responsive and you can tune the opening rate of the secondaries to suit the engines needs.
    Mark Whitener
    http://racingfuelsystems.myfunforum.org
    __________

    Good work isn't cheap, and cheap work can't be good.

  10. #10
    Junior Member SHOW GUEST
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    i went from 750 to 650 also

    i have 358 14.5-1 motor heads flow 230 cfm started with 750 went 7.53 with a 1,59 60 ft then put a 650 on it went 7.17 with a 1.46 60 ft and i dont understand that unless my 750 was not right

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