deck the heads.

Discussion in 'Small Block Tech' started by nekkidhillbilly, Feb 5, 2021.

  1. nekkidhillbilly

    nekkidhillbilly escaped mental patient

    how much should i deck the heads on my 72? trying to stay on 87 octane so i dont want a super high comp ratio. having them ported as well by a local guy soon. should i get larger exhaust valves done as well?
     
  2. sean Buick 76

    sean Buick 76 Buick Nut

    The trick is to match the compression ratio with the camshaft you are using. What year engine is it? Which pistons? Depth of pistons in the hole? Which camshaft etc?

    Larger valves can give large gains but only if the cam and compression are high enough to take advantage of the larger valves.
     
  3. rkammer

    rkammer Gold Level Contributor

    Sounds like you're after some increased performance so why only use 87 octane fuel? It's a fun car so build the motor for 91 or 93 octane pump gas. It won't cost that much more to drive it.
     
  4. sean Buick 76

    sean Buick 76 Buick Nut

    agreed, I would shoot for 9.5:1 static compression if using a mild cam like a TA-212 or 10:1 or more if using a larger cam
     
  5. LARRY70GS

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

    Last edited: Feb 6, 2021
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  6. alec296

    alec296 i need another buick

    I would go with both intake and exhaust valves, potential gain would be more . If your sticking to 87 octane, as mentioned, cam makes a difference to your dynamic compression. So you probably will have only .030 milled for about 8.75 on a 68-74 350 with stock low compression pistons and fel pro head gasket. The 212 cam is a decent choice, I would still suggest the crower level 3 cam . Then the big task would be tuning. You can tune for the octane you will be using. Preferably in hotter weather. Where spark knock may be more prevalent.
    your rear axle gear ratio will also affect spark knock, if engine can climb faster, less load on engine. So a 3 series rear gear and a higher torque converter will change performance and possible timing requirements.
    What gears, converter,trans, cam do you intend to use?
     
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  7. 72gs4spd

    72gs4spd Well-Known Member

    I would pick your cam first. Then you would be able to determine the static compression that will deliver the dynamic compression your comfortable with. I personally think you should consider higher compression and run premium fuel.
     
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  8. Fox's Den

    Fox's Den 27 years of racing the same 355 Buick motor

    yep what they said^^
     
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  9. Mark Demko

    Mark Demko Well-Known Member

    12.1 to 1 use race gas:p:D
     
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  10. nekkidhillbilly

    nekkidhillbilly escaped mental patient

    i have a cam very similar 212 sean and the reason like i mentioned before this car is going to get drove super long distances. it recommends around 9.0 over the 8.5 factory. should still run 87 fine. im just curious how much i would need to deck them to get them up to base of 9.0 or so from the the stock 8.5 so i know what to tell the machine shop. or should i just run thinner gaskets and call it good.
     
  11. nekkidhillbilly

    nekkidhillbilly escaped mental patient

    342 with the 700r4 i have and the s10 covertor.
     
  12. nekkidhillbilly

    nekkidhillbilly escaped mental patient

    Cam Type Stage 2 High Performance
    Exhaust Duration 224
    Exhaust Duration at .050 inch Lift 224
    Exhaust Lobe Centerline 117
    Exhaust Valve Lash Hyd.
    Exhaust Valve Lift .310
    Exhaust Valve Lift with Factory Rocker Arm Ratio .465
    Intake Duration 214
    Intake Duration at .050 Inch Lift 214
    Intake Lobe Centerline 107
    Intake Valve Lash Hyd.
    Intake Valve Lift with Factory Rocker Arm Ratio .443
    Lifter Type Hyd

    its a engine tech stage 2. looked very similar to the ta212.
     
  13. alec296

    alec296 i need another buick

    S10 converter may stall alittle higher on the 350. The
    the 212 will still make more power then this cam. mill heads about .040. For about 48 cc heads and 8.94 compression. Bigger valves may take up a bit of the chamber increasing compression a tiny bit more.
    recheck duration . Duration and duration at .050 are not usually the same.
    I’m gonna suggest a Quadrajet Power or Everyday Performance built Quadrajet for this combo. n
    Do not go with a single plane intake manifold.
    If those specs are correct, I think your dynamic compression will be pretty high.
     
  14. sean Buick 76

    sean Buick 76 Buick Nut

    I'm not sure if I would even mill the heads more than you absolutely have to. Maybe 10 thou to clean them up. Then sure run low octane fuel and have fun on long trips with less cost.
     
  15. nekkidhillbilly

    nekkidhillbilly escaped mental patient

    welp looks like rockauto is selling these for buick 350s and its a chevy cam? i looked on enginetechs site and its listed as small block chevy. i dont think a sbc and buick one interchange do they? i know nothing else does.
     
  16. alec296

    alec296 i need another buick

    No Chevy cams do not work or fit a Buick 350.
     
  17. nekkidhillbilly

    nekkidhillbilly escaped mental patient

  18. sean Buick 76

    sean Buick 76 Buick Nut

    Yes I think that is a SBC cam and Rockauto is wrong saying it will fit. I did a quick search and couldn't find any low $ options. Crower has sales once in a while but not at the moment. A few years ago they were selling high performance cams for $39 so I bought a bunch LOL. But those are big big cams for racing.
     
  19. nekkidhillbilly

    nekkidhillbilly escaped mental patient

    yeah its been since xmas so i guess ill have to ebay it. i sent them a email since its on there end they should make it right but i wont think that will work since its past there return policy. nice cam if you know anyone that wants a good chevy cam. so with the crower or the 212 what should i be looking at decking and what are my options for inexpensive valve springs? i had springs as well lol. idk if those swap. lifters may be the right part however. ill have to go look at the box.
     
  20. nekkidhillbilly

    nekkidhillbilly escaped mental patient

    got the right lifters. sean iirc the ta212 runs ok on stock springs right? im just going to bite that bullet i think.
     

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