Rebuilt 425 now junk?

Discussion in ''Da Nailhead' started by 56buickboy, Aug 5, 2007.

  1. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    Not sure if this is true,but years ago some one told me(can't remember whom) that when they started making 425s to lower manufacturing costs they casted the 401s and 425 the same(posibily more towards the end of the production of the Nail Head engine years) ,and just machined them different with the 425 with a bigger bore.

    That being said the later 401s might be able to be bored out to a 425 bore size. I have never did any sonic testing to confirm this "rumor", if anyone has any sonic tested 65-66 401s block data to confirm this,it would be good to know,and appreciated thanks in advance. We could compare Ross's data with if some one has the mentioned 401 data. Both of these engines did come off the same assembly line,so it is a posibility. (yes,they even had bean counters back then)
     
  2. doc

    doc Well-Known Member

    Well, guy,,,, my thoughts are this....basicly, you are looking at the cost of sleeving all 8 cyls. vs the cost of buying a block here in the states.. and making sure that it will not be cracked some where or other condition that would make it unusable....and the hassle of shipping it to you..... if you sleeve all 8 , you can probably go ahead and run the .060 over pistons that you have.... because you are adding thickness of STEEL to the walls, not cast iron.....
    i would think that you will need a heavy duty radiator for that puppy.... and a 7 blade fan.... i am thinking that you need a better machine shop or you need to really clamp down on that one if they are the only one around.... that is a major blunder , not catching a bore through condition... and then saying that you could go a head and use it??????
    kind of like a 401 that I had that the machine shop ruined the cam bearings on... then said they were ''just fine''.... looked like they had been reamed with a hand saw..... nope , not in my engine.....
    Get knowledgeable of the engine and then get tough on what you expect from a shop.....and in this day and age of the internet you dont have to take a shop telling you to get it done somewhere else.... that shop blundered and they ''owe you''.... all you have to do is spread the word if they dont make it good.....
    the shop here got such a bad rep. that they went out of business.....
     
  3. telriv

    telriv Founders Club Member

    Doc, Ross stated that he bought a rebuilt engine from the States. When he tore it down this is what he found. Nothing to do with any machining done by shops for him. I meant to say #1-3 & 5, not 7 @ 118"-120" & 120".. And looking again closer #6 @ .096". You can only offset bore it by .020"-.030" & East-West only ( front-rear) NOT North or South (top-bottom) as it would change the angle from 90*. There is enough movement in the rod/pin in the piston to allow this.
     
  4. doc

    doc Well-Known Member

    Hmmmm, I missed that..... :Brow:
     

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