318 to 340

Discussion in 'Small Block Mopar Engine' started by Moparbaker, Nov 6, 2018 at 3:28 PM.

  1. Moparbaker

    Moparbaker Active Member

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    I'm wondering about if there's any use to bore a 318 to a 340 or would the cylinder walls become to thin then?
    Anyone who's done that? & how good & reliable would it be for daily use?
     
  2. MoparMike1974

    MoparMike1974 Well-Known Member

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    Not enough meat in the block.
     
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    • 72Dart6pack

      72Dart6pack Harder Better Faster Stronger.

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      Try it. Let us know how it goes. Keep us posted.
      :thumbsup:
       
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      • 66fs

        66fs Well-Known Member

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        Not worth it anyway. It is best to have the thickest cylinder walls you can. 4.04 - 3.91 = .13. +1/8 of an inch bigger bore, .06 per side, same stroke, not much difference if you put all the good 340 stuff in a 318.
         
      • Hellrats

        Hellrats Still wrenching after all these years FABO Gold Member

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        LOL... Your mean :lol:
         
      • 72Dart6pack

        72Dart6pack Harder Better Faster Stronger.

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        340's are so over rated
         
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        • Divenut

          Divenut Well-Known Member

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          Hey! We made it to post #6 before the 340 haters chimed in! LOL ;)

          Pat
           
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          • 72Dart6pack

            72Dart6pack Harder Better Faster Stronger.

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            Skipped over 340 & went right to 408 Six Pack.
            :thumbsup:

            IMG_24951.jpg
             
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            • 72Dart6pack

              72Dart6pack Harder Better Faster Stronger.

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              Bet we can drag this Bad Boy post out to 3 or 4 pages.
               
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              • 72Dart6pack

                72Dart6pack Harder Better Faster Stronger.

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                Hydraulic or solid cam? In this clone 340? Power will peak around 5400. So no need for a forged crank. :poke:
                 
              • 318willrun

                318willrun Stomper 4x4... we kept energizer in business

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                Bore a 360 .040 over and put a 318 crank in it = 340 :D
                 
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                • 273

                  273 Well-Known Member

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                  A 0.030 - 0.060 over bore 318 is a decent size. Unless building a 500 hp plus engine build a 318 as if it was a 340 you aint gonna notice much of a difference especially if geared and stalled properly.
                   
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                  • 72Dart6pack

                    72Dart6pack Harder Better Faster Stronger.

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                    Just tell people it's a 340. Problem solved.
                     
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                    • Go Mango

                      Go Mango Well-Known Member

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                      My 70 swinger 4 speed car has a 340. It was rebuilt many years ago by Sam Jones of early 60's NHRA fame. I don't know what he did to it, but it's a wicked little beast with the factory 3.91 gears. Best engine I've ever owned.
                       
                    • nm9stheham

                      nm9stheham Well-Known Member

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                      FWIW, I just measured a standard bored 273 block that had pretty nice walls. If it was bored .065" on all walls, it would end up at .120" minimum on any thrust face, and .115" minimum on any front or rear wall. It might work out for just driving around if you found a 318 block with such even walls. But as said, there are better ways to get to what is desired.
                       
                    • Max1196

                      Max1196 Well-Known Member

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                      No no no , put the 360 crank in the 318 and then you've got a 340nine
                       
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                      • 72Dart6pack

                        72Dart6pack Harder Better Faster Stronger.

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                        Are we on page #2 yet? Lol
                         
                      • 408 swinger

                        408 swinger FABO Gold Member FABO Gold Member

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                        Don't forget the ported 906's and 509 cam and, oh shit! 340 not 440. My bad! Bwahahahahaha!
                         
                      • 318willrun

                        318willrun Stomper 4x4... we kept energizer in business

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                        Didn't you read? The OP want's a 340, so it has to be my way :D
                         
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                        • 72Dart6pack

                          72Dart6pack Harder Better Faster Stronger.

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                          So should put X Heads or TA Heads on this clone 340? Just throwing the topic out there.
                           
                        • Go Mango

                          Go Mango Well-Known Member

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                          I'd imagine the OP feels like he was asking a legit question, and didn't expect to be poked fun at.
                           
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                          • abodyjoe

                            abodyjoe Well-Known Member

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                            Sonic test the block and see if it will go that far safely.
                             
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                            • gliderider06

                              gliderider06 Well-Known Member

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                              Why not just put a 4" stroke in it? More cubes than a 340. Much better than paper thin cylinder walls and lots more torque. My $0.02
                               
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                              • SWED67barracuda

                                SWED67barracuda Well-Known Member

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                                Hi , posted a comment on this in the thread 340 just under this one
                                 
                              • Hellrats

                                Hellrats Still wrenching after all these years FABO Gold Member

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                                No bore a 360 .040 over and call it a 340 stroker!