When to run a stall converter?

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

  1. Reidk

    Reidk Well-Known Member

     
  2. Reidk

    Reidk Well-Known Member

    My pistons
     

    Attached Files:

    Mark Demko likes this.
  3. Mark Demko

    Mark Demko Well-Known Member

    Those look low compression to me.
    On the SP3, on my build, I noticed very very little if any loss of low end torque with the SP3 VS a dual plane.
     
    70skylark350 and Reidk like this.
  4. Reidk

    Reidk Well-Known Member

    That's good to hear about the intake. What cam are you running? And do you have stock pistons? Are you running a stock converter?
     
  5. Reidk

    Reidk Well-Known Member

    Top pic is a true low compression piston. Bottom pics are 20201121_180613.jpg mine. Am I being too optimistic to think that mine aren't dished quite as much?
     
  6. Mark Demko

    Mark Demko Well-Known Member

    Cam is a TA roller
    Measured 11.1 to 1 compression, forged Auto Tec pistons.
    9.5" JW convertor, stalls @ 3000, flashes to 3500, drives like a stocker.
     
  7. alec296

    alec296 i need another buick

    Might have to cc them. Check part number. 1231899 it looks like on my 71 pistonsthey don’t look as dished as the 71 but definitely not a hi compression
     

    Attached Files:

  8. Mart

    Mart Gold level member

    Did you find steel shim head gaskets when you removed the heads?
     
  9. Reidk

    Reidk Well-Known Member

    Yes
     
  10. Reidk

    Reidk Well-Known Member

    I dont plan to pull my pistons. How much should I mill off the heads to be close to 9 to 1?
     
  11. alec296

    alec296 i need another buick

    bout .030 should give a 50 cc head ,with the .024 head gasket nets about 9.03
     
    Reidk likes this.
  12. Mart

    Mart Gold level member

     
    Last edited: Nov 22, 2020 at 8:00 AM
  13. Reidk

    Reidk Well-Known Member

    Alec suggests taking.030 off the heads to get me close to 9.03. My cam specs 9:1 heads will be in the shop this week.
     
  14. 70skylark350

    70skylark350 Well-Known Member

    my motor is a 72 350. custom JE pistons with 9.5:1 compression. heads ported and polished. stock exhaust manifolds. Quadrajet carb set up by Ken at Everyday Performance. TA 284 cam 475"-223'/.475"-230',110'. 2800 stall converter from Jim, TA stage 1 dual plane aluminum intake. Letric Limited points eliminator, posi 2:93 out of a 69 GS. Sounds great at Idle, just enough lump. runs great. running through the same exhaust as I had on the stock low compression 2 barrel motor but sounds completely different. I would like to step up to a 3:42 rear gear, she would be a rocket off the line.
     
    alec296 likes this.
  15. Mart

    Mart Gold level member

    ^^ Good.
    Cams respond to more compression. That's all you can do without opening up bottom end & ordering custom forged pistons:)
     
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  16. Reidk

    Reidk Well-Known Member

    I'll be running the same cam but I have large tube headers and a single plane intake.
     
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  17. Reidk

    Reidk Well-Known Member

    My pistons are #1231899
     
    alec296 likes this.
  18. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    Yes I would mill the heads 30 thou and use shorter pushrods
     
  19. Reidk

    Reidk Well-Known Member

    Will I really need shorter pushrods?
     
  20. alec296

    alec296 i need another buick

    Hit or miss on the pushrod. You may or may not.hard to say since you already had the thin head gasket. ​
     

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