My 350 build getting closer need some advice

Discussion in 'Small Block Tech' started by Storm1, Oct 4, 2019.

  1. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Read some cam shaft descriptions. The reason they specify minimum static compression ratios is to get the DCR in the ball park. Your reasoning is back wards. Decide the cam you want to run FIRST, then make sure your static compression is correct for that cam. Nothing wrong with post 14. If you plan on aluminum heads, you'll want a higher SCR. Now that you have the calculator, have a look at the TA cams and play with the numbers.
     
  2. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    Do you have flow numbers for your heads?
     
  3. Mart

    Mart Gold level member

    In 1st post.
     
  4. Mark Demko

    Mark Demko Well-Known Member

    I tried the Q-jet on the SP3, its ok except when slamming to WOT, theres no accelerator pump on the secondary side of the Q-Jet, so the engine shuts off, LOL seems like it, then recovers. A DP carb is needed with the SP3 in my opinion, go 850 cfm. DONT listen to the people at Summit Racing that will tell you "that's way too big":rolleyes:
    Call/contact Jim Weise about a custom convertor for YOUR build.
    Im at 11.1 to 1 compression, no detonation heard on 93 pump gas, BUT Im convinced my 9.5" Jim Weise convertor has a lot to do with it, the engine is not allowed to bog, or experience excessive load.
     
  5. Mart

    Mart Gold level member

    That's where the 410 gears shine.......

    Mark, post your cam card for Kevin to check out. He's looking at different grinds.
     
    Mark Demko and Dano like this.
  6. Storm1

    Storm1 Silver Level contributor

    I did plan on getting the converter from Jim. It looks like at least a couple people are running high compression on pump gas. That may or may not work depending on the cam I pick. It wont be a full race cam, probably something between a bracket/street cam.

    Mark, just curious, what's your DCR? Can you post your cam card?

    Right now I'm just plugging numbers in the calculator. I've found a lot that wont be a good fit with my build, and 1 (so far) that looks decent.
    I want to deck the heads the least amount possible to get to the right compression ratio for the cam I pick.
     
  7. Mark Demko

    Mark Demko Well-Known Member

    I’ll look for my cam card when I get home. IIRC it’s .536 lift and around 239@.050 it’s a roller cam.
    Good idea tho on the JW converter;)
     
  8. Mark Demko

    Mark Demko Well-Known Member

    Heres my cam card from my post when I received my cam. IMG_0994.JPG IMG_0995.JPG
     
  9. Mark Demko

    Mark Demko Well-Known Member

    I know I know:D:D:D:D:D
     
  10. Storm1

    Storm1 Silver Level contributor

    Thanks Mark

    If I change the lobe to 110, it might be a good fit for me.

    Why the 113 lobe?
     
    Mark Demko likes this.
  11. Mart

    Mart Gold level member

    Mark,
    You have a funky cam there....... .355 lobe height X 1.6 rocker ratio = .568 valve height, not .586
    Either that or should be 1.65 ratio rockers.
    Did you catch that already?
     
    Mark Demko likes this.
  12. Storm1

    Storm1 Silver Level contributor

    Is a quench distance of .025 too close?

    I rechecked some numbers.

    Im not .011 in the hole
    I'm .005

    Double checked heads are at 62cc
     
  13. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Why don't you just use a .040 head gasket?
     
  14. Storm1

    Storm1 Silver Level contributor

    That would put me at 6.96 DCR - 9.32 SCR - .047 quench

    That's nowhere near the 7.50 DCR you said I should shoot for
     
    Last edited: Oct 8, 2019
  15. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Maybe I missed what cam you are using, the same one in your 1st post?
     
  16. Storm1

    Storm1 Silver Level contributor

    Yes, changed head to 62cc and deck to .005 w/4° advance (which i didn't add in the above numbers) Im getting

    7.21 DCR
    9.32 SCR
    With the .042 gasket

    Does that calculator figure quench to the rim of the dished pistons? Or the actual dish?
     
  17. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Yes, confirmed. I'd say you need a custom cam unless you increase the static compression.

    Or, if you run a TA212 cam straight up, I get 7.58 DCR.
     
    Last edited: Oct 8, 2019
  18. Storm1

    Storm1 Silver Level contributor

    What's the down side of running with a .025 quench if I have dished notched 16.5cc pistons?

    Heads are above deck .020
    Pistons in the hole .005
    7.51 DCR
    9.74 SCR


    I see the interwebs say quench should be somewhere between .030 .040 but I don't know why .005 below that range would be bad?
     
  19. Mark Demko

    Mark Demko Well-Known Member

    Yes:D it was either you or someone else pointed that out to me when I received it way back when, maybe it’s a “mystery cam” lol:eek:
     
  20. Mark Demko

    Mark Demko Well-Known Member

    Honestly don’t know, when I ordered the cam from Tim at TA, that’s what he recommended as the roller cams in the 350 were “uncharted territory “ at the time, that’s how Tim explained it.
    Maybe someone on here can explain the difference between a 110 and 113 LC.
    Told Tim I was going to run 11 to 1 comp. ratio.
     

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