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  1. #1
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    Default Engine vibration

    84 Ltd lx 347, t5, 8.8
    Just installed a 347 and it has a vibration at 2000 rpm, vibration is very noticeable in neutral or on the road. I used the fly wheel, pressure plate and clutch from the previous engine, 302 out of a 1989 mustang gt.

  2. #2
    FEP Supporter Broncojunkie's Avatar
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    Every 347 kit I've seen was externally balanced at 28oz. The oem 302 as of (iirc) 81 is 50oz. That's probably your issue. Flywheel/flexplate and harmonic balancer need to match.
    79 Pace Car - 331, t5
    79 Cobra - working on 351w, t5
    82 Capri- working on 302, t5
    82gt - working on 408w, c4

  3. #3
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    Thanks, I thought it might be something like that. The engine came with a flex plate.

  4. #4
    FEP Supporter Broncojunkie's Avatar
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    Maybe you could look up a part number on the flex plate to confirm the balance?
    79 Pace Car - 331, t5
    79 Cobra - working on 351w, t5
    82 Capri- working on 302, t5
    82gt - working on 408w, c4

  5. #5
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    I sold the flex plate. The guy I bought the engine from said the engine rotating assembly is balanced 28 oz.

  6. #6
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    I drove the car down the road for 2 miles, I hope it didnt hurt anything.

  7. #7
    Moderator wraithracing's Avatar
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    Default

    As mentioned most stroker kits are balanced to the 28oz flexplate/flywheel and harmonic balancer. The minimum you need is a 28 oz flexplate and a 28oz harmonic balancer as mentioned above Broncojunkie. If the stroker kit came with the balancer and the flexplate those would have been the better choices to use, but may not be an option at this point.

    As for damage, probably not. I wouldn't recommend running or driving the engine until you get the situation sorted out though. Good luck!
    ​Trey

    "I Don't build it hoping for your approval! I built it because it meets mine!"

    "I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."

    Mustangs Past: Too many to remember!
    Current Mustangs:
    1969 Mach 1
    1979 Pace Car now 5.0/5 speed
    1982 GT Stalled RestoModification
    1984 SVO Still Waiting Restoration
    1986 GT Under going Wide Body Conversion Currently

    Current Capris:
    1981 Capri Roller
    1981 Capri Black Magic Roller Basket Case
    1982 Capri RS 5.0/4spd T-top Full Restoration Stalled in TX
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  8. #8
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    I have a 28 oz flywheel ordered.

  9. #9
    FEP Supporter Broncojunkie's Avatar
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    A buddy of mine used a 50oz balancer and flywheel on a 28oz engine, despite me urging him not to. He just insisted on "trying it anyway". After everything was together, his reply was "everything seems to be fine other than a vibration". I continued urging him not to run it but he was daily driving it about 60 miles a day and beating the snot out of it. A couple months into it, his engine came apart. He was really surprised for some reason. All I could do was shake my head. You can lead a horse to water lol!
    79 Pace Car - 331, t5
    79 Cobra - working on 351w, t5
    82 Capri- working on 302, t5
    82gt - working on 408w, c4

  10. #10
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    I have pulled the transmission and removed the flywheel. I have ordered a new flywheel. Thanks for the info.

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