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Technical 393 Windsor carb size

Discussion in 'Traditional Hot Rods' started by rocketsled59, Oct 2, 2017.

  1. rocketsled59
    Joined: Mar 14, 2010
    Posts: 494

    rocketsled59
    Member

    i have a 2800lb 64 falcon 393 Windsor and a four speed. 12:1 ,pro comp 190cc heads with 1.94 2.02 valves. Single plane high rise. 305 duration .540 lift flat tappet cam. It's a race engine. I'm running a 750 double pumper and am concerned I'm under carbureted. What size carb are you guys running on your ford stroker drag race engines? I'm not running near my potential. Only 1.64 60' times. I'm hooking up. Just seems lazy. Mph sucks.
     
  2. Gammz
    Joined: May 10, 2015
    Posts: 512

    Gammz
    Member
    from Lincoln Ne

    Have you pulled your plugs after a run and see what's they look like? What RPM are ya dropping the clutch at?


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  3. Deuces
    Joined: Nov 3, 2009
    Posts: 12,414

    Deuces
    Member
    from Michigan

    Roughly 725 cfms should do it.... Or, I could be wrong....
     
    Last edited: Oct 2, 2017
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  4. LM14
    Joined: Dec 18, 2009
    Posts: 572

    LM14
    Member
    from Iowa

    Fords like carbs if they have good heads. I think you probably have 2.02/1.60 valves (not 1.94/1.50 I hope). 190cc runners are on the small side for a 393 in my opinion. I would have gone 210cc or more for a drag engine with the extra cubes and the higher compression. What crank did you use? If it's a cast crank, you may not want to turn it that hard. I see nothing wrong with a 750 on a 393 Windsor but the heads may be what is holding you back at this point. A lot depends on how hard you plan to turn it. If you aren't turning it past 7000 RPM you may be better off with a 650 or 700 because of the smaller runners and low RPM. The only time the engine can really use the whole carb is on the top end. We ran everything from a 390 to a 980 on our dirt engines and we turned them to 9200 (they had Ernie Elliot CNC top end and the best internals you could buy). RPM and potential to pull air is what sizes the carb. Good tuning is a must when you reach that level.

    JMO,
    SPark
     
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  5. RmK57
    Joined: Dec 31, 2008
    Posts: 453

    RmK57
    Member

    I'm running a 750 Q series Quick fuel on 502 BBF in a 57 Ford. I'm probably a little under carbed, but it seems responsive enough. Runs mid-11's, 1.55-1.60 60 ft's.
     
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  6. rocketsled59
    Joined: Mar 14, 2010
    Posts: 494

    rocketsled59
    Member

    Need to look at plugs. Bout 3500 on the launch.
     
  7. rocketsled59
    Joined: Mar 14, 2010
    Posts: 494

    rocketsled59
    Member

    My bad. Typo. 1.60/2.02. Cast scat. I figured with the torque I would have no need to spin it more than 6500. ??? That's why I went with 190. Figured I'd have more port velocity
     
  8. squirrel
    Joined: Sep 23, 2004
    Posts: 37,409

    squirrel
    ALLIANCE MEMBER

    if the carb it a bit smaller than it could be, that should not adversely affect the 60' time....but it might affect the MPH through the traps

    edit:

    have you played around with ignition timing?
     
  9. Gammz
    Joined: May 10, 2015
    Posts: 512

    Gammz
    Member
    from Lincoln Ne

    Wind her up!! Easy for me to say eh?


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  10. rocketsled59
    Joined: Mar 14, 2010
    Posts: 494

    rocketsled59
    Member

    Started to put some timing in it at the track fri nite but my timing light didn't work. So no I haven't
     
  11. rocketsled59
    Joined: Mar 14, 2010
    Posts: 494

    rocketsled59
    Member

    My buddy said leave at 4000
     
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  12. RmK57
    Joined: Dec 31, 2008
    Posts: 453

    RmK57
    Member

    I read somewhere about hooking up a vacuum gauge and at wide open throttle you shouldn't have anymore than 1.5 hg. Anymore than that then there is a restriction.
    It would be easy enough to try and see if there's anything to it.
     
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  13. Gammz
    Joined: May 10, 2015
    Posts: 512

    Gammz
    Member
    from Lincoln Ne

    That's a start....... I saw your other thread about your clutch. That might need more attention if your gonna flat foot it and dump it!


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  14. saltflats
    Joined: Aug 14, 2007
    Posts: 7,099

    saltflats
    Member
    from Missouri

    How do you have your headers set up?
     
  15. rjones35
    Joined: May 12, 2008
    Posts: 565

    rjones35
    Member

    is this the same vehicle having the clutch problems? maybe they're related?
     
  16. rocketsled59
    Joined: Mar 14, 2010
    Posts: 494

    rocketsled59
    Member

    1 5/8" fenderwell It probably doesn't breathe that well. I'd like to build new ones 1 3/4"
     
  17. rocketsled59
    Joined: Mar 14, 2010
    Posts: 494

    rocketsled59
    Member

    Yes. But 60' is somewhat consistent. 1.64-1.67. I'm not the fine tune guy. Fuckn frustrated. I really thought this thing would run elevens easy.
     
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  18. saltflats
    Joined: Aug 14, 2007
    Posts: 7,099

    saltflats
    Member
    from Missouri

    How long are the primary tubes?
     
  19. deathrowdave
    Joined: May 27, 2014
    Posts: 641

    deathrowdave
    Member
    from NKy

    An engine is basically an air compressor moves air in moves air out . Over carbing can be as bad as not enough , it's a fine line to get correct . Read the plugs and let her eat !
     
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  20. rocketsled59
    Joined: Mar 14, 2010
    Posts: 494

    rocketsled59
    Member

    40"
     
  21. saltflats
    Joined: Aug 14, 2007
    Posts: 7,099

    saltflats
    Member
    from Missouri

    Sounds like a header for building torque a shorter tube would help with higher RPM power.
     
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  22. RmK57
    Joined: Dec 31, 2008
    Posts: 453

    RmK57
    Member

    What et and mph? What kind off power does the engine make? Stock suspension? Rear gear ratio?
    Fuel pressure at end of run? Not nearly enough info to make any suggestions.
     
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  23. rocketsled59
    Joined: Mar 14, 2010
    Posts: 494

    rocketsled59
    Member

    Stock leafspring rear with ladder bars. Straight axle up front. 4:11 not sure how much power. I was shooting for 500+ but I think it's far short at this time. 12.46 / 108. Don't know fuel pressure at end of run. 6 1/2 lb at idle. Gauge is under hood.
     
  24. rocketsled59
    Joined: Mar 14, 2010
    Posts: 494

    rocketsled59
    Member

    Wondering about schoenfeld imca headers for fenderwell headers. Bigger tube and collector.
     
    Last edited: Oct 3, 2017
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  25. southcross2631
    Joined: Jan 20, 2013
    Posts: 1,601

    southcross2631
    Member
    from Florida

    You basically have to pull the stopper out of the bottle. With your 393 you have too small header primaries. Should be at least 1-3/4 ,probably 1-7/8 . If it is a drag car then I have a nice solid roller that is .600 lift that would wake that thing up. You need better heads ! A good choice would be the CNC ported AFR 205 heads maybe even the 220 's. .
    A well set up 393 with a stick can run a 950 on a single plane . With that much compression and good heads and a solid roller cam you should be closer to 600 hp. I know spending more money hurts, but speed costs money.
    That car at that weight should be knocking on the low 10's easy.
    I am playing with the idea of building a 293 cube motor for my gasser and I would need 1-3/4 primaries and at least .640 lift cam and 2 660's on a tunnel ram. I would have to have at minimum a 205 head. You are a 100 cubes bigger and have choked the motor . It is like pouring water through an 1/4 inch line versus pouring water through 2 inch line. Which one will fill a bucket faster ?
     
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  26. RmK57
    Joined: Dec 31, 2008
    Posts: 453

    RmK57
    Member

    A 2800 lb. car with 450 hp should be running mid to lower 11's. If the car seems to be laying over I'd be looking at the fuel system or bad valve springs or both. The 1 5/8 headers aren't holding you back that much if at all.
     
  27. rocketsled59
    Joined: Mar 14, 2010
    Posts: 494

    rocketsled59
    Member

    How can I set up a gauge to monitor fuel pressure inside car? Not big on fuel line inside the car. Wondering if my 3/8" fuel line is too small??
     
  28. squirrel
    Joined: Sep 23, 2004
    Posts: 37,409

    squirrel
    ALLIANCE MEMBER

    see if you can put one on the cowl, just in front of the windshield.
     
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  29. RmK57
    Joined: Dec 31, 2008
    Posts: 453

    RmK57
    Member

    I bought a length of brake line and went from a port in the fuel line to the firewall then up the cowl where it meets the hood. Made a bracket to hold the gauge, a couple sheet metal screws and it's done.
    It was only supposed to be temporary, but it's still there, the tech guys at the races said it was ok to use.

    3/8" fuel line should be fine as long as it's not kinked and your using the right fittings.
     
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  30. saltflats
    Joined: Aug 14, 2007
    Posts: 7,099

    saltflats
    Member
    from Missouri

    105-2413.jpg
    The diaphragm will have to mount forward of the firewall.
    The line going to gauge is filled with antifreeze and has to be bled to work correctly.
     
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