1. dirty white boy

    dirty white boy 50 yr old Juvenal delinquent

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    can a 85 318 be line bored .310 over to accept a 2.81 360 main journal?
     
  2. Jadaharabi

    Jadaharabi FABO Gold Member FABO Gold Member

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    That would make the main webbing and the main cap bolts kind of close to each other and the main cap a little thin on top.(bottom of cap that is)
     
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    • Jadaharabi

      Jadaharabi FABO Gold Member FABO Gold Member

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      Here is the forged 3.58 crank with the 318 or 340 mains.

      CHRYSLER Mopar Performance P5007253 Mopar Performance Forged Crankshafts | Summit Racing - Free Shipping on Orders Over $99 at Summit Racing
      CHRYSLER Mopar Performance P5007253 Mopar Performance Forged Crankshafts | Summit Racing


      And here is the cast version.

      CHRYSLER Mopar Performance P5007257 Mopar Performance Cast Crankshafts | Summit Racing - Free Shipping on Orders Over $99 at Summit Racing
      CHRYSLER Mopar Performance P5007257 Mopar Performance Cast Crankshafts | Summit Racing

      Might be cheaper just have the mains turned down on your 360 crank to the 318 340 size.
       
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      • dirty white boy

        dirty white boy 50 yr old Juvenal delinquent

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        ive looked at them many times, figured it many ways, to many! wish some body made a 3.70ish small journal crank!
         
      • Jadaharabi

        Jadaharabi FABO Gold Member FABO Gold Member

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        I think you can get a 3.79 stroke crank.
         
      • Jadaharabi

        Jadaharabi FABO Gold Member FABO Gold Member

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        • dirty white boy

          dirty white boy 50 yr old Juvenal delinquent

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        • Moparpuller

          Moparpuller Active Member

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          Molnar also has a 3.79 stroke
           
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          • RustyRatRod

            RustyRatRod I didn't do it. FABO Gold Member

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            It's possible. If the shop really does it the "right" way and just barely skims the block so as not to move the crank up and make a stock timing chain loose, it might take too much off the caps. How thick are they to begin with? At .310, you might as well say you're removing 5/16 (.312) from the cap. That's a lot. Plus then, you'd need to have the bearing lock machined back in. I speck it could be done, but should it?
             
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            • RustyRatRod

              RustyRatRod I didn't do it. FABO Gold Member

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              Why not just turn the crank down?
               
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              • Jadaharabi

                Jadaharabi FABO Gold Member FABO Gold Member

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                It's a circle so you'd only be cutting half of that .310 out
                 
              • yellow rose

                yellow rose Overnight Sensation FABO Gold Member

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                ^^^^^^THIS^^^^^ just turn the crank down. How do you think it was done in the 1970’s?
                 
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                • RustyRatRod

                  RustyRatRod I didn't do it. FABO Gold Member

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                  How much have people been hackin off 440 cranks to go in 400s? A lot. Not as much as .310, but a lot.
                   
                • Jadaharabi

                  Jadaharabi FABO Gold Member FABO Gold Member

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                  People only do that to the 400s when they want to go fast.
                  If God allows it.
                  I'm going to have a 360 crank cut down and put in a 318 with a 4-inch bore.
                  You ask why? Why would you put a 360 crank and pistons in a 318?
                  Because I want the markings for the 318 on the side of the block. But I want it to run better than a stock 318.
                   
                • RustyRatRod

                  RustyRatRod I didn't do it. FABO Gold Member

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                  Not a damn thing wrong with that. You couldda just said "cause I want to" that's reason enough.
                   
                • dirty white boy

                  dirty white boy 50 yr old Juvenal delinquent

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                  yes it makes more since to turn the crank, cheaper to, not to mention smaller bearing =lower bearing speed! just thinking to much i guess! looking for a different way around the same block, weighing all options!
                   
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                  • MOPAROFFICIAL

                    MOPAROFFICIAL FABO Gold Member FABO Gold Member

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                    You can't do it "line bore wise" on a 318 cap. there's not enough meat in it no matter what anyone says. It wouldn't last. you have to change the cap if you wanted to even attempt to approach it in such a way...and use studs, not bolts and all that short of threads nonsense.

                    Turn the mains down or buy a crank.
                     
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                    • mopardude318

                      mopardude318 Well-Known Member

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                      I like that. Cheap enough. As far as needs finishing, is that on both rod and main journals to the respected size? 331&379.
                      Probably.
                       
                    • Max1196

                      Max1196 Well-Known Member

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                      And is still done these days!
                      100_3186.JPG 100_3184.JPG
                       
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                      • yellow rose

                        yellow rose Overnight Sensation FABO Gold Member

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                        That forging (could be a casting...I didn’t look at the link) needs every machining process done to it, including the flange and snout.

                        You have to find a crank grinder with the skill to do it, will do a one off one time deal and then he has to WANT to do it. Those ain’t easy to find. I looked into that and the only one I could find to do it was Marine Crankshaft, and he wasn’t all that enthusiastic about it.

                        His exact words were “unless you need some oddball stroke to get into a class what you want is certainly cost prohibitive”.

                        I think he was at 800 bucks on the low side and a grand on the high side.
                         
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                        • mopardude318

                          mopardude318 Well-Known Member

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                          Yea, I ain’t into that. Lol.
                           
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