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Thread: 4.5" stroke?

  1. #1
    mrgoslow

  2. #2
    mrgoslow
    c'mon 6 views no response. can you put a 4.5 crank in a 9.8 block? wouldnt r/s ratio be less than desirable?

  3. #3
    Infomaniac
    Yes you can do it.
    And yes r/s ratio would suck. It sucks in a 10.2 block
    Using stock length rods or even .250 long they are doing something fancy with the pistons or counterweights to clear.

  4. #4
    Carnivalride
    c'mon 6 views no response. can you put a 4.5 crank in a 9.8 block? wouldnt r/s ratio be less than desirable?
    Ok here's my .02,
    9.8-(4.5/2)-rod length=wrist pin height and deck clearance.
    with the stock 6.135 rod length you have a 1.415 remaining for the wrist pin. Probably do able but a 1.36 r\s ratio sucks!
    with the 6.385 rod, 1.165, probably unlikley but 1.42 r/s ratio still sucks.
    Hope this helped some.

  5. #5
    steelcomp
    these guys are both right...besides, you'd be pulling the piston so far out the bottom of the cyl, you'd probably crack the skirt. The piston would be so short it would want to go sideways...terrible ring sealing, tons of drag, (friction/side load) and the acceleration/deceleration of the piston would be really hard on rods and the crank. And it's actually 525.2 ci.
    with the 6.385 rod, 1.165, probably unlikley but 1.42 r/s ratio still sucks
    That would give you .67" to the top of the pin. With two rings your oil pack would be in the middle of the pin...not unheard of, and could go with single ring, but with 1.42 RR, why would you for only 525 ci?

  6. #6
    Raylar
    This is the spec on our new 496 stroker motor, but its a 10.2" block with a 6.700 rod. Not the greatest ratio but the non-siamese bore 496HO block will only allow about a .030 overbore in its thin cylinder bore casting. We are dyno testing now and we've seen some pretty impressive numbers already and we really like the torque curve and power band width.
    Raylar :hammer2:

  7. #7
    steelcomp
    That extra .400" makes a lot of difference.

  8. #8
    mrgoslow
    yup, thanks

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