400/450 stroker....Cheap parts, lotta work.

Big Block A body Tech

  1. fishmens67

    fishmens67 FABO Gold Member FABO Gold Member

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    Thank you for sharing your attention to detail.
    It's the little things some of us never think of that make a difference.
     
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    • IQ52

      IQ52 Well-Known Member

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      Sorry for the delay............

      400-450 rockers 004.JPG
       
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      • IQ52

        IQ52 Well-Known Member

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        The first 400/451 stroker that we did needed the block ground along the indicated red line at the junction of the main webbing and the bottom of cylinders 4 & 8. This being necessary to clear the modified 440 crankshaft counterweights. With this engine I have .050" of clearance from the crankshaft counterweight. If it hits with that much clearance I have some other kind of really big problems going on.

        400-450 crnk clearance 005.JPG 400-450 crnk clearance 006.JPG .
         
      • qkcuda

        qkcuda Well-Known Member

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        Did you turn down the couterweights, and you still only have .050 clearance?
         
      • IQ52

        IQ52 Well-Known Member

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        Yep. They hit on a previous engine that had the crank ground exactly the same way. Life can be so damn cruel.
         
        Last edited: Mar 4, 2021
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        • 1968rt

          1968rt Well-Known Member

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          I wonder if those rockers are home made or factory experimental?
           
        • RustyRatRod

          RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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          Jim, cool build. Thanks for sharing all this.
           
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          • RustyRatRod

            RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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            I think I remember Jim sayin his pappy whipped those up.
             
          • IQ52

            IQ52 Well-Known Member

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            See post #47............
             
          • RustyRatRod

            RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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            Oh ok. Thanks. How are they made? Hard to see the inside. Is it a threaded sleeve welded to the rockers? Pretty cool idea.
             
          • IQ52

            IQ52 Well-Known Member

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            It looks as if it is a threaded insert shaped like a mushroom tappet that is pressed into the rocker arm from the underside. I don't see any welding and there is proud metal pushed up around the outside of the insert on the top of the rocker arm.
             
          • RustyRatRod

            RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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            Wow and it stays put. Imagine that. I'd be skeered.
             
          • IQ52

            IQ52 Well-Known Member

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            Cody and I have done some strange things with those rockers. In 2007 or 08 we used them on a 7.5:1 compression, stock rod, cast piston, 383 that made 525 HP at 8,000 rpm on the Westech Performance Group dyno in Mira Loma. It was the same day our '71 Road Runner with a pump gas 451 made 554 RWHP on the chassis dyno there. My boys and I were dashing back and forth between the engine dyno and chassis dyno wearing out our track shoes.
             
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            • RustyRatRod

              RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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              I went back and reread. You say the mushroom is on the BOTTOM side and they are pressed in FROM the bottom? That would work then, since that's the wan the pushrods' force is. Or did I read that wrong? Interesting for sure.
               
            • IQ52

              IQ52 Well-Known Member

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              You have it correct Rob. They are pressed in from the bottom.
               
            • RustyRatRod

              RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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              Ok, then I might not be as skeered. lol
               
            • 66fs

              66fs FABO Gold Member FABO Gold Member

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              You guys paying attention? Wow!
               
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              • IQ52

                IQ52 Well-Known Member

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                Imagine, using the Crane Gold Race rockers we had to make a rocker shaft relocation kit here at the shop to move shaft this much. It will reduce the sweep across the valve tip from .110" wide to .040" wide. 400-450 rocker correction 009.JPG

                Offsetting the holes in the shaft...........
                400-450 rocker correction 001.JPG 400-450 rocker correction 003.JPG

                We ended up with this.........I can make the upper clamps this beefy because the lash adjusting screws on the rocker arms stick up higher at full lift than the rocker clamp nuts do.
                400-450 rocker correction 008.JPG
                 
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                • IQ52

                  IQ52 Well-Known Member

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                  Lordy, knocking all the burrs off by hand wasn't fun. And I had to do six of the bottom spacers again because they came out .035" too tall and moved the the pattern off center towards the exhaust port exits and spread it out to .050".

                  400-450 rocker correction 002.JPG

                  You can kinda see the pattern on the left valve without the correction kit. It is off center towards the intake port openings and .110" wide. The valve on the right, using the correction kit, has a sweep pattern of .040" and is centered on the valve tip. Bad picture but it is the best I could do for now.
                  400-450 rocker correction 006.JPG
                   
                  Last edited: Mar 10, 2021
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                  • oldkimmer

                    oldkimmer FABO Gold Member FABO Gold Member

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                    U will have more hours in this build than ur customers race builds. Kim
                     
                  • LowDeck451

                    LowDeck451 Well-Known Member

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                    A few years ago, I think it was you or Challenger340 that posted pictures of how and where to grind the block and crank for a 400/451. The counterweights had a 45* cut on the edges and the block was ground in the area you’re showing IIRC? His point was, a guy could do this part at home and not pay the machine shop. Does this sound right? Thanks.
                     
                  • 66fs

                    66fs FABO Gold Member FABO Gold Member

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                    Are these corrections to stock length valves? Or should we be checking factory setups to see how far off they are?
                     
                  • IQ52

                    IQ52 Well-Known Member

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                    Seems like anytime you go to a roller tipped rocker arm there will be corrections to be made. These are very close to standard length valves.
                    I've seen the post to which you refer but I had nothing to do with it. The method I've posted is the only way I have done it.
                     
                  • RustyRatRod

                    RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                    I thought all that was required was turning the counterweights down. Is there a reason you do it differently?
                     
                  • IQ52

                    IQ52 Well-Known Member

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                    I'm guessing that Chrysler didn't always machine the 400 blocks exactly the same. Sometimes just cutting the counterweights down clears and sometimes you grind the block or the edge of the counter weights also. Supposedly some just do a major 45 degree bevel on the counterweights by number 4 and 8 cylinders and don't cut them all .120" in radius on the lathe like I do.
                     
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