Performance street SBC build

Discussion in 'Engine Topic' started by jakob stevanus, Nov 8, 2021.

  1. jakob stevanus

    jakob stevanus New Member

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  2. jakob stevanus

    jakob stevanus New Member

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    Is porting the bowls expensive for shop to do ? Of they will serve me well I can have them cleaned up Also I have engine apart now and have some photos of cylinder walls do they look ok ? I am new to these engines aslo looked like this engine is already .30
     

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  3. jeff swisher

    jeff swisher Veteran Member

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    Yes porting is expensive for a shop to do it.
    Cylinder walls look fine from here I would run them as is.
    That sbc is just a bigger pushrod engine treat it just like a Harley.
    More lift more duration on the cam more compression better valve springs same stuff as the Harley.
    Just another air pump.

    I ported my first set of heads before I was of legal drinking age.
    Had a black and decker drill and 1 hard stone that was blue in color and shaped like a Christmas tree.
    I bowl ported them and picked up 4 tenths in the 1/4 mile.

    Cam swaps on that stock 350 Olds did not get me that much gain.
    A drill and a stone and blend that huge ridge .. Think about how the air must move through a tube (intake runner)
    If you put a brick in the tube it will kill the flow.
    Blend the edges of that brick and air flows around it better.. remove it and it gets much better.
     
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  4. jakob stevanus

    jakob stevanus New Member

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    Thannk you makes sense . And specific cam duration and lift you can suggest . I think I'll have the machine shop make sure tolerences are good on bore and try to run .030 pistons maybe same ones but new rings if shop says they are good if not I'll go Mahle .030 with the small metric rings . I will consider trying to do the heads my self any video you can suggest to get an idea ? Shop quoted me 1100 for the head work so new heads would be better if I had to go that route
     
  5. jeff swisher

    jeff swisher Veteran Member

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  6. jakob stevanus

    jakob stevanus New Member

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    Thank you
     
  7. sandlapper

    sandlapper Veteran Member

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    OP jakob
    where are you at in the world ? Not exactly, but within about 100 miles or 160 Km ?

    do ya really wanna dump lotsa money into an old flat tappet, 2 piece RMS block that's already +0.030" over ? (in MTC parlance that's "third over" or + 0,75mm)
     
  8. jeff swisher

    jeff swisher Veteran Member

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    I got a .030" over recently that I am building and the piston to wall was a bit tight with my Mahle forged pistons.
    I had the block honed with fine stones a tick less than .001"
    The bores are now all 4.031" perfect for my pistons and the RPM I plan on twisting it.

    I also took my crower rods and the pistons/rings and pins and the scat crank to the shop to have it balanced and I had the block decked .010" it all cost me $460 not bad really.

    I have stuck them together for much less and much less machine work and they also lived.
    Found out today the Free Vortec heads I got are both cracked.
    On the search for possibly aftermarket vortecs or run some of my 601 heads again.

    It will all add up in the end.
     
  9. jakob stevanus

    jakob stevanus New Member

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    Waterloo area Ontario Canada. And don't really want to sink a ton ... Might try to use the heads I have. They look to be in good shape . If I disassemble to port the heads my self Cann I re use valves and get new spring with a camm kit . or should it all be new . If pistons and cylinders are cleared good from shop I'll keep as is if they are flat tops and It has higher compression. One thing I noticed is the head center bolts for intake are angled different and the intake holes were elongated just on the middle ones is this ok ? . If I have to sink $$ I will I would like to have the 350 in it because that's what it came with and I want to restore the original minus some engine and drivetrain performance . if I cannot get decent power from what I have Now I will spend the money what kind of hp would I ball park have with the 350 @ .030 with the swirl heads bowl ported or stock and a. Decent cam ( I have No idea what cam to use ) High 2s or low 3s ?
     
  10. jeff swisher

    jeff swisher Veteran Member

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    Elongated holes in that intake are fine.. done it often.
    You could get by fine with those pistons and your power levels and rings in a Moly faced variety.

    350 Hp easy with bowl blend and a smallish cam 218 @.050 110 lsa.
    Want more step up to 224-230 at .050 cam.
    Still streetable and not too hard on the wallet.
    I usually reach for the [email protected] .050 for a good effort budget deal.
    I do spend money on Crower cam saver lifters and Pac Beehive springs though 313 spring rate.
    Never lost a flat tappet since using that setup.
    Gibbs break in oil is always used and their hot rod oil is excellent.
    Now called Driven oil.
    NO additives needed. I use their break in assembly grease also.
     

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