Max RPM for conventional headed blown Chevy

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by Neil Morley, Mar 24, 2018.

  1. Neil Morley

    Neil Morley Member

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    hey guys what's your opinion on maximum RPM for a blown BBC with stainless not titanium valves on a conventional headed BBC ?
     
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  2. sammy christian

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    Only my experience, 8300 with T&D stuff on top and .937 lifters.
    The heavy valves are risky after that.
     
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  3. jay70cuda

    jay70cuda Member

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    You could use titanium intake valves and prolly go higher. But why risk it.
     
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  4. Blownalky

    Blownalky Top Sportsman

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    With titanium, I normally shift at 8600. Been up to 9200 but no power there with my combo with about 475 on the seat and a C rotor. When I had stainless, pretty sure I went to about 8,000 but was with a different cam and heads. 2.300 and 1.880 on the stainless with 11/32 stems.
     
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  5. Neil Morley

    Neil Morley Member

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    Yeah I'm running the BMF 385cc cylinder heads with a stainless 2.30 intake valve with titainium retainers with a 55 mm cam .904" lifter with TandD shaft 1.8 rockers cam specs are .819" lift intake.810" lift exhaust duration @.050" 280int. 290exh on a 114 LSA with the blower @ 38% OD it makes 40lbs boost and the motor is a 555 CI. the springs were set up with 340lbs on the seat and around 1000 on the nose, I have my shift point set at 7600 and the rev limiter set at 8100 but by the time the tranny catches it it routinely hits the rev limiter and with a 4.56 gear and a 33" tall tire it's pretty much on the limiter at the 1/8, my valve train looks beautiful when I inspect it with no signs of valve float and looking at the data logger the motor seems to be in its happy spot and still making power so I'm just wondering if I could raise my limiter safely another couple hundred RPM since I know it's not happy on the rev limiter?
     
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  6. jay70cuda

    jay70cuda Member

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    I think you’re plenty safe no seeing those numbers. Touching the rev limiter will knock the springs outta it in a hurry. I don’t think you should have them set so close to each other. I would think the stroke on that crank would be enough of a rev limiter.
     
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  7. sammy christian

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    sounds like you are keeping up on your stuff well so it shouldn't be a problem. Watch the exhaust valves when you start spinning it higher, that is where I had trouble.
     
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  8. TAFC 5 81

    TAFC 5 81 Member

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    Back in the Pro Comp days we pushed ours 8000-8500 but had a smaller cam (703 lift) and 1.7 rocker ratio.
     
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