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  •  » 347 failure.

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    6/11/2026 1:43 PM  #1

    boss347convertible
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    Registered: 4/22/2013
    Posts: 174

    347 failure.

    After 22 years of use, the 347 in my 66 failed while on tour. Driving from Huntington Beach to Carmel, approximately, 125 miles into the trip, cruising approximately 65 in overdrive, a loud cracking noise came on and I immediately pulled onto the shoulder. I called a tow truck and while waiting for 5 hours, removed the driver's side valve cover and all looked normal. Had I pulled the passenger side valve cover, I would have seen part of the problem, but decided to wait as I knew the engine would not be running.

    Next day, things started to become clearer upon dissasembly. I tried to post photos, but without success, so I will just explain that a valve either broke, struck the piston or a combination of both.

     

    Last edited by boss347convertible (6/11/2026 1:46 PM)

     

    6/11/2026 2:59 PM  #2

    Rudi
    Senior 24-7 FYI Addict

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    From: Stuck in the 50's Welland Ca
    Registered: 4/01/2013
    Posts: 4,103

    Re: 347 failure.

    Sucks to hear that!
    How many miles on it?

    Good work ain't cheap, Cheap work ain't good!
     

    6/11/2026 3:10 PM  #3

    Steve69
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    From: Madison Wisconsin
    Registered: 4/01/2013
    Posts: 2,820

    Re: 347 failure.

    Sorry to hear that.  22 years is a good run.  How many miles did you have on it?  Whats your plans to replace your engine?

     

    6/11/2026 3:18 PM  #4

    boss347convertible
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    Registered: 4/22/2013
    Posts: 174

    Re: 347 failure.

    Miles are in the 80-90k range. Mostly hard/fun miles. I have no complaints. Replacement engine will be a 363 that I will detail in a separate post.

       •Thread Starter
     

    6/12/2026 5:16 AM  #5

    BobE
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    From: White Plains, NY
    Registered: 4/04/2013
    Posts: 3,011

    Re: 347 failure.

    Sorry to hear about the failure, good luck with the new enginee. 

    65 Fastback, 351W, 5-speed, 4 wheel discs, 9" rear,  R&C Front End.
     

    6/12/2026 8:03 AM  #6

    RTM
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    From: Cape Coral FL
    Registered: 5/22/2019
    Posts: 2,109

    Re: 347 failure.

    Sorry to hear that but it did last a good spell and sounds like it provided a lot of fun along the way.

     

    6/13/2026 5:41 AM  #7

    Nos681
    Senior 24-7 FYI Addict

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    From: Atlantic Mine, Michigan
    Registered: 7/14/2016
    Posts: 3,571

    Re: 347 failure.

    Sounds like new engine will be fun too.

     

     

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