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  1. #1
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    Default Square bore or Spread Bore on a Torqupower manifold

    Hi Everyone

    Im thinking of purchasing a Quickfuel HR580 vacuum secondary electric choke carb. I think it is squarebore. I currently have a torquepower single plane manifold with a 750 Holley Vac Sec carb which is a pain in the backside. Do you know if this quickfuel will suit my manifold. I guess I could easily check by removinf the current carb but not sure if I should do that yet.

    A link for my current manifold

    hq-wb single early heads

    My motor is nothing off the planet just a mild 308

    Red Heads unknown work
    Perhaps a lumpy cam as my vaccum is very low and jumps over the place sounds lumpy.
    Straight cut timing gears
    Gilmer Belt Drive
    Torque power single plain manifold
    Genie extractors
    3 inch exhaust.

    Car is not very tunable use to be an ex turbo setup so maybe the powervalve and fuel jets are oversized thinking about trying the quickfuel see if it solves my problems.

  2. #2
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    Default

    It's a decent size manifold. Might be a bit much for your application.

    Why is it not tunable?

    Sent from my SM-G930F using Tapatalk

  3. #3
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    I bought the car like this I dont really want to go mucking around changing the manifold I was hoping to just swap the carb out and make it more tuneable. Its the first ever single plane hi rise manifold Ive ever owned and I do notice most people go for the dual plane. The car when I bought was setup for drag racing fuel cell in boot etc. I have slowly being turning it back to street car. Put a standard fuel tank back in and an external fuel pump. To tell you the truth it runs pretty good and hard with the 750 holley it doesnt really have any flatspots etc. My problem arisses with the car running way to rich. Its filtyh rich the tailpips is soaked in soot and its that bad the car idling in a garage r even out of it just stinks like petrol I just really want to tone that down.

  4. #4
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    If it runs smoothly without any flat spots, and pulls hard you're already above the curve with the Holley. Have you tried adjusting idle mixture for best engine vacuum, or if it has a big cam that bounces vac gauge needle, for highest rpm?

    I wouldn't have thought if it was a turbo the cam lsa would be higher and the cam not overly big.

    Sent from my SM-G930F using Tapatalk

  5. #5
    Do you ever leave? EH179's Avatar
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    Yes, squarebore, and i would pick the 680cfm over the 580.

  6. #6
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    Quote Originally Posted by narva*2010 View Post
    If it runs smoothly without any flat spots, and pulls hard you're already above the curve with the Holley. Have you tried adjusting idle mixture for best engine vacuum, or if it has a big cam that bounces vac gauge needle, for highest rpm?

    I wouldn't have thought if it was a turbo the cam lsa would be higher and the cam not overly big.

    Sent from my SM-G930F using Tapatalk
    Ive hooked up a vacuum guage and its very very low vac and jumps alot. I have tried tuning it and no matter what I do its always pig rich and fuelly. It likes to not have the idle mixture screws wound in to much or it just stalls etc. NO idea of what cam it has but it does sound pretty lopey could be the timing gears and gilmer belt though? Its also a m21 4 speed with brass button clutch and a 4.11 vl turbo diff so she doesnt ever see very high rpms either

  7. #7
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    Quote Originally Posted by bfhoon View Post
    Ive hooked up a vacuum guage and its very very low vac and jumps alot. I have tried tuning it and no matter what I do its always pig rich and fuelly. It likes to not have the idle mixture screws wound in to much or it just stalls etc. NO idea of what cam it has but it does sound pretty lopey could be the timing gears and gilmer belt though? Its also a m21 4 speed with brass button clutch and a 4.11 vl turbo diff so she doesnt ever see very high rpms either
    Does it still run with idle screws all the way in?

    Sent from my SM-G930F using Tapatalk

  8. #8
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    I had a 650 dp on a mild/hot 308 for 20 years. Was brilliant.

  9. #9
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    No way it stalls well before they are wound all the way in

  10. #10
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    Quote Originally Posted by RedTaxi View Post
    I had a 650 dp on a mild/hot 308 for 20 years. Was brilliant.
    Thats what this thing needs 650DP, none of this VAC SEC nonsense...

  11. #11
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    Quote Originally Posted by paulzig View Post
    Thats what this thing needs 650DP, none of this VAC SEC nonsense...
    Really? I thought a double pumper would just dump more fuel than a vac secondary?

  12. #12
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    Nah, dp's run mostly on the primaries. Secondaries only open when you want them to. About the last 1/3 of throttle.
    Vac carbs and chokes have no place on a Holden V8 imo. I've never needed or wanted them.

  13. #13
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    Dp all the way and a bit easier to understand /tune especially when one puts a man cam and compression in it.

  14. #14
    Sure why not? 76lxhatch's Avatar
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    Any carb will require some disassembly to tune to suit your engine and vehicle, with different parts (e.g. jets) to be swapped to achieve the desired result. Unless you happen to be very lucky nothing will be just bolt on and go, don't fall into the trap of expecting to be able to swap the whole carb for a magic fix.

    I completely disagree with not needing a choke, if you have your carb well tuned it will be a pain in the neck when cold without one, and it doesn't interfere with hot running. Many carbs (particularly Holleys) are too rich in standard trim which hides this but when you get it sorted you get better economy and power, and the choke becomes useful.

  15. #15
    254RWHP boat anchor EVL253's Avatar
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    i done that thread on how to tune a holley for economy for a reason. that 750 with some work could work fine. one in the thread is sitting on a stock 302 clevo running good.
    if you were to go dp remember this. the idle circuits etc are usually tuned rich.
    if you want it the best it can be NO carb is goong to be a straight bolt on proposition!
    11 second E85 bottle fed boat anchor

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