When to run a stall converter?

Discussion in 'Small Block Tech' started by Reidk, Nov 16, 2020.

  1. Reidk

    Reidk Well-Known Member

    I'm getting ready to order a Holley brand 50cc pump cuz the quickfuel is on backorder. Will I have to have a carb spacer? Just looking at my intake and carb it doesn't look like I will need a spacer for the 50cc pump to clear.
     
  2. Reidk

    Reidk Well-Known Member

    Is a carb spacer required with the 50cc accelerator pump ?
     
  3. Mart

    Mart Gold level member

    I don't think so. 50cc is only abt 3/16" thicker than the 30cc.
    I've always run a spacer to get the dual feed fuel line up and away from intake runners.
    Some of the 50cc kits have a thin pump arm. Try and get the heavier style arm.
     
  4. Reidk

    Reidk Well-Known Member

    3/16 means that 1 screw head will be extremely close. Everywhere else should clear good.
     
  5. Mart

    Mart Gold level member

    3 posts back you can see my frt 50 pump, I do have a spacer though.
    You can double gasket the carb to intake for a bit more room if needed.

    I've bought Holley accessories from this seller. Decent stuff and prices...
    mrmanifold,
    https://www.ebay.com/str/rpmperformanceproducts
     
    Last edited: Feb 28, 2021
  6. Reidk

    Reidk Well-Known Member

    Found this interesting post on another forum Screenshot_20210228-175929_Samsung Internet.jpg Screenshot_20210228-175939_Samsung Internet.jpg by a barry grant tech.
     
  7. Reidk

    Reidk Well-Known Member

    50cc pump is installed and I'm Making progress. Check video. I have a vacuum reading between 9 and 10 at idle in gear. So I plan to order a 4.5 power valve. Also going to order a steering column mounted tach today. My car pulls hard from 100 to 110 mph but I didnt want to go much faster in 2nd gear without a tach. Shifting to 3rd drops me out of the power band pretty quickly.

    In the video you'll see that it'll do 13 seconds to 80mph and 19 seconds to 100mph with current carb set up.

     
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  8. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    WOT shift points will be governor weights. Modulator only adjusts minimum and part throttle shift points, and only within a narrow range (2-5 MPH).

    I think gears and a converter will be a real eye opener. You can hear the engine when it gets into the cam's power range. The converter and gears will get you there much quicker. At that point you might need to re tune the carburetor again.
     
    Last edited: Mar 6, 2021
    Reidk likes this.
  9. Mart

    Mart Gold level member

    Yes, much better. Without Gears & convertor for now, you need to hold and shift manually.
    You are on your way!:)
     
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  10. Reidk

    Reidk Well-Known Member

    I think you're right for sure about the rearend and stall. But I dont want to go too low and lose highway mpg. If I can find a BOP rearend that's a direct bolt in I think I'd look for something in the low 3s but will that be enough of a change to justify all of the work?

    Is there a kit with different governor weights? Can they be changed with tranny in the car?
     
  11. Mart

    Mart Gold level member

    Throw MPG & gas mileage out the window when you're hotrodding.:D
    Fast & economy don't go hand in hand. :)
    You sure can't burn regular octane....
     
  12. Reidk

    Reidk Well-Known Member

    What kind of difference will I notice with the correct power valve? I'm going from a 6.5 to a 4.5. I read that a power valve is worth 10 jet sizes of fuel. So getting that too soon is clearly a problem but I'm not sure what to expect.
     
  13. Reidk

    Reidk Well-Known Member

    I live in a rural area though and anytime I drive it to town or around to do estimates itll be a minimum 50 mile trip. I dont necessarily want to be taching 3 grand at 55mph everywhere I go. That's why I really need the tach installed. Want to see where I'm at now
     
  14. Mart

    Mart Gold level member

    2 things will get you where you want to be, 373-410 gears and a 2004r o.d. trans. :)
     
  15. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    3.08's will be a pretty good compromise. The converter will help as well. I'd go 3.23 as a minimum if it was me. Try the converter first.

    https://www.summitracing.com/parts/bmm-20248

    Yes, the governor is under a round cover. You will lose some fluid when you remove it. Getting the back of the car up high helps. Then it is modify and test. It will take several tries to get it exactly where you want. It's a good idea to get a spare governor and modify that. That way you can always go back to stock if needed.



    The transmission in the video is a 700R4, but the 350 has the same type of cover.
     
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  16. Reidk

    Reidk Well-Known Member

    My 88 firebird had a built 350 with 373s and overdrive. I'd bury the needle at 135 and it kept going. That is ultimately the setup I would want with this car.
     
  17. sean Buick 76

    sean Buick 76 Buick Nut

    my 75 Regal has 2.56 gears and a 2004R trans, 140 mph is easy without high revs. The engine is done up pretty good though too.
     
  18. Mart

    Mart Gold level member

    I had 308 gears. Not enough fun, and definitely not what I would consider a performance gear.
    In 1970, my dad had a new SS396 Chevelle that we drove from MI to FL with a 355 gear. 2k mile round trip running 70+ down I75. They can take the rpms, it's just your ears that keep hearing that little voice that keeps saying "shift already". :D:D
     
  19. Fox's Den

    Fox's Den 355Xrs

    You are probably shifting at 4500 on its own out of first sounds like. The power valve will do nothing when on the floor this will just keep the power valve from turing on at part throttle until your vac drops to 4.5 then the valve will open to supply more gas at that point. Power valve is just that a valve from part throttle to power.

    No 3800 lb car with a 256 gear and a 350 is going to hit a 140 mph with a overdrive no way no how. the rpm will be too low for the engine to pull it out. Not without real gears out back. I want to see that video.

    Wind out first gear more it should do 55 in low gear and 100 + in second You might hit 120 in third but the engine will be too low on rpm to pull it out. 342 gear will pull to 120 in 3rd.

    You keep playing with the shooters and the cams on the carb till it burns a little rubber like it does now and you will have it.
    Those tires breaking loose will let you know if you are going the right way with the carb.
    When you do those tests from dead stop do it the same way each time you make an adjustment to the shooters and cams.

    At least you have some wide open spaces to do that some of us had to do this in the city (not guilty).

    If you have those screw in air bleeds on your new carb Leave them alone and don't play with them you will screw the whole carb up. I am going to talk to Mart on this later on today.
     
  20. Reidk

    Reidk Well-Known Member


    Burning a little rubber from a stop consistently is where I'm at now. I have the best combo of pump cams installed. I went through them all yesterday. The Yellow cam on the primary took care of 90% of my issues. blue on the secondary got me to where I'm at now. During the process i tried some that killed the car from a launch. have a 28 and 33 squirter coming. It ran similar with bigger squirters it was hard to tell much of a difference by going smaller but every article I read said you want just a big enough squirter that you dont bog. This car does not bog any more. It dont launch great but that's to be expected with my gears and converter. The 28 squirter with the 50 cc pump will probably be too long of a shot. Causing it to go rich maybe. I Think the 33 will be perfect. Im also using a hollow nozzle screw.

    I wont mess with bleeds until I get my afr. I'm really just trying to dial in the basics right now like pump shot, power valve, idle mixture screw etc

    I have a tach coming, a 1/2" air cleaner spacer, and some more squirters. Should be here next week.
     

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