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  1. #1
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    Default Help me pick a Carby 308 holden

    Hey Everyone

    Im going to ditch my current 750 holley mechanical secondary Carby thats currently on my 308. Its running really really fuelly tailpipe black kills me in the garage when its running as its filthy rich. Wondering what is my best option I have been told quickfuel carbs are the goods what should I choose obviously a 750 is to big on my motor I want to eliminate it and run not so rich. Motor specs below

    Hq 308 Block and Hq Pre pollution red Heads. Not sure of bore standard valve springs im assuming standard pistons unsure though car use to be a 308 turbo
    4 speed m21 manual
    Brass button clutch
    4.11 diff ratio vl turbo lsd.
    torquepower single plane hi rise manifold
    Currently 750 holley Vac Secondaries Carb
    10 mm Ignition leads
    Standard dizzy I think not sure if its been re graphed due to running a 308 turbo
    Crane Cams HI6 Electronic Ignition system
    Genie Extractors.
    External fuel pump currently running 7 psi at pressure regulator.
    Straight cut timing gears
    Gilmer belt Driven.
    Fan clutch no a/c or power steer.
    Cam Iam unsure it does sound really really lumpy not sure if thqts the exhaust gilmer drive straight cut gears etc. Im assuming it might have a cam it was an ex turbo 308. Pretty sure before I bought it they just whacked the turbo off and put on genie extractors without spending a cent or worrying about anything else.

    Thanks

  2. #2
    casual poster 1time's Avatar
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    Loads of adjustability on a quickfuel..

    The real question is why do you want to buy a whole new carb just because the idle is rich? What's stopping you just spending some time learning how to dial in the current carb

  3. #3
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    Why not fit the good old Quaddie?
    Lots of info out there to help tune them.

  4. #4
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    Quote Originally Posted by 1time View Post
    Loads of adjustability on a quickfuel..

    The real question is why do you want to buy a whole new carb just because the idle is rich? What's stopping you just spending some time learning how to dial in the current carb
    Ive been told multiple times by multiple people a 750 holley vac sec or mechanical is way way to big for my motor maybe if it was a 355 fine but no a mildish 308 way to large so I have been told by many many people

  5. #5
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    Quote Originally Posted by Ponza View Post
    Why not fit the good old Quaddie?
    Lots of info out there to help tune them.
    Been there done that had a quaddie many times on a warm 308. Ive had them tuned by the best.

    advantages. qucik easy start doesnt take long to warm up and idle properly. Good and reliable. Never had one where you can smash the throttle and have instant power. there is always a slight hesitation which is very awkward feeling on hard acceleration. Ive had them tuned and jetted by the best but its always been a complaint of mine. Apart from that yes good relaible carb. The 750 holley I have at the moment awkward at low rpm and slow cruising I smash the throttle though and its right there no hesitation instant power I love it unfortunately massive fuelly tailpipe black as its filth.

  6. #6
    Do you ever leave? paulzig's Avatar
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    Quote Originally Posted by 1time View Post

    The real question is why do you want to buy a whole new carb just because the idle is rich? What's stopping you just spending some time learning how to dial in the current carb
    Yeah, a set of jets are a lot cheaper than buying a new carburetor.... Running a stock distributor with the stock advance curve will do it too.. You need to work out what initial and total is and have it regraphed too...

  7. #7
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    Quote Originally Posted by paulzig View Post
    Yeah, a set of jets are a lot cheaper than buying a new carburetor.... Running a stock distributor with the stock advance curve will do it too.. You need to work out what initial and total is and have it regraphed too...
    What jets would you suggest? Im happy to buy a new dizzy with a normal graph curve if anyone can suggest ?

  8. #8
    Do you ever leave? paulzig's Avatar
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    Quote Originally Posted by bfhoon View Post
    What jets would you suggest? Im happy to buy a new dizzy with a normal graph curve if anyone can suggest ?
    See whats in there first and drop down jet sizes until its leaner, but at idle you'll need to check the idle circuit too, make sure the main screw isnt too far in as it exposes the slots... The stock magnetic bosch distributor it just needs a regraphing. Its a manual so dont lock it up put a curve in it like 15-18 initial and 32-34 total all in around 2500-3000.
    If you go buy a 600or 650 mech secondaries that'll need tuning and distributor advance sorted out too...

  9. #9
    E B
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    get it regraphed.
    got mine done last week by Hume performance, runs much better now.
    If no repairs needed, $150 and back in a week or so.
    Mine was a bit worn and needed extra work so cost a bit more and took a bit longer, but runs much better now.
    Give them a call and tell them as much as you can about the engine and they will work out a good setting.
    If you don't know the specs of the cam, you can try profiling it with a degree wheel and dial indicator, so they get the dizzy curve right.
    Where abouts are you anyway?

  10. #10
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    Quote Originally Posted by E B View Post
    get it regraphed.
    got mine done last week by Hume performance, runs much better now.
    If no repairs needed, $150 and back in a week or so.
    Mine was a bit worn and needed extra work so cost a bit more and took a bit longer, but runs much better now.
    Give them a call and tell them as much as you can about the engine and they will work out a good setting.
    If you don't know the specs of the cam, you can try profiling it with a degree wheel and dial indicator, so they get the dizzy curve right.
    Where abouts are you anyway?
    Im in Newcaslte. Would have no idea on how to dail in cam. Ive intalled one before with an apprentice mechanic but he took care of most of it. So I would have no idea on checking. It sound pretty lumpy so I assume it may have one.

  11. #11
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    ive ran a 750dp on 308 with 286 cam and ran wonderful started up easily and AF were great best time run was 12.98 in a vb sle over 20 yrs ago .

    Get someone who knows his shit about carbs and it will work !

  12. #12
    been here .......too long Smitty2's Avatar
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    Quote Originally Posted by bfhoon View Post
    Been there done that had a quaddie many times on a warm 308. Ive had them tuned by the best.

    advantages. qucik easy start doesnt take long to warm up and idle properly. Good and reliable. Never had one where you can smash the throttle and have instant power. there is always a slight hesitation which is very awkward feeling on hard acceleration. Ive had them tuned and jetted by the best but its always been a complaint of mine. Apart from that yes good relaible carb. The 750 holley I have at the moment awkward at low rpm and slow cruising I smash the throttle though and its right there no hesitation instant power I love it unfortunately massive fuelly tailpipe black as its filth.
    you obviously did not have the Quaddie tuned/set up correctly!
    with a Quaddie on the race car, the other guys I regularly run against
    know they cannot out grunt me out of corners, instant and easily modulated
    throttle response and it breathes all the way up to 7000
    (no flatspots ... plus that incredible Quaddie intake noise when the secondarys open)

    Sandown.. 2 weekends out of T4, its raining and hailing, car has a spool in the diff
    and taken on a phone by one of the guys in the club, throttle control needed here

    a very short video here (hopefully runs ok)

    https://youtu.be/s3LfOfOQDEI
    Last edited by Smitty2; 13-09-2017 at 08:13 PM.
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  13. #13
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    The L34 with the H.O. kit made good horsepower with a 780 Holley on top of it. Fairly radical cam though.

  14. #14
    been here .......too long Smitty2's Avatar
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    Quote Originally Posted by Shiney005 View Post
    The L34 with the H.O. kit made good horsepower with a 780 Holley on top of it. Fairly radical cam though.
    yeah.. and it was never used on the race track
    all the better teams swapped to webers or dellortos
    coz the Holley made hp but no grunt no torque out of corners




    and...

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  15. #15
    E B
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    sounds like best bet would be to get the carb tuned properly on a dyno.
    I know a couple places in Seven hills and Blacktown area (western Sydney), but unfortunately no one up your way.
    I'll ask a mate who lives that way if he knows anywhere.

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