Flexplate Bolts

Discussion in ''Da Nailhead' started by NailheadinCA, Aug 30, 2002.

  1. NailheadinCA

    NailheadinCA Buick Nut

    Hey Guys,

    Can anyone tell me the specifications on the Flexplate bolts for my 65 401. I didn't get a flexplate or bolts with the motor I bought to rebuild and I want to purchase new ones not used. I was told today that I could use 7/16" chevy bolts, has anyone done this? I am inserting the pistons and crank into my block this weekend and the project is moving forward with more speed all of the time. I don't want a small inexpensive part to hold me up. Any help would be great and appreciated.

    Ralph Nicastro Jr.
    64 Skylark 401 CID.
    Southern California
  2. Justin

    Justin Active Member

    you can get SS ones from Alloyboltz.com. They have stainless parts for all your nailhead needs.
  3. DugsSin

    DugsSin Well-Known Member

    Hi Ralph here's what is on my 401's/425's
    7/16 bolt is correct, shaft must be completely threaded,bolt shaft length is 5/8 and that will bring it 1 or 2 threads through the crank flange.
    Socket size for the head of bolt is 5/8 and there are three slashes on head of bolt.
    What have you done to the bottom end so far for the rebuild?
  4. Zach Collie

    Zach Collie Groovy,Baby!

    Hi Guys! Also take note of the threads per inch count. Those bolts are probably going to be "fine" thread, somewhere around 24-28 TPI. The three marks on the head, if in a "star" pattern would denote a grade five bolt. As long as you keep the length correct, and the thread pitch right you can use pretty much anything grade five or above. I usually use grade eight bolts or some really strong stainless ones that I get from a company called WURTH. They're probably equal to a grade ten!(very strong). Hope this helps... Zach.
  5. NailheadinCA

    NailheadinCA Buick Nut

    Hey GUYS,

    Thanks for the info on the flexplate bolts. I am going to compare them to the ones that are on the market for chevy's as I think they are exactly or close the same.


    I have so far, bored the block .060" over and used badger pistons, checked the rods for straightness and size, installed new freeze plugs, had the block mic'd and magnafluxed of course and the crank work done. I have moly rings for it as well. The whole shootin match is balanced and waiting for ten minutes time to put it all together (this Weekend I hope). I have ordered the high pressure oil pump from Carmen Faso in New York and am going to order the cam from him as well. I am going to be using the top end (Rebuilt of course) from my current 401 in my skylark right now and the 750 holley as well. I have the skylark exhaust manifolds but am curious if the riviera headers from TA performance would work well or if at all.

    Let me know if you have any suggestions from experience as all are welcome and appreciated. Thanks

    Ralph Nicastro
    Norwalk, CA:beer

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