How Big can a 5.2 get?

Magnum Engine Swaps

  1. Dusterfreak

    Dusterfreak Well-Known Member

    Messages:
    122
    Likes Received:
    19
    Joined:
    Aug 29, 2010
    Location:
    Finland
    Local Time:
    11:09 AM
    What size can a 5.2 be bored over? I know alot of older 318`s been bored for 340 pistons but how about magnums? I just got a 5.2 thats been sitting and its got rust in the cylinders so an overbore is a must...
     
    • Thanks! Thanks! x 1
    • toolmanmike

      toolmanmike FABO Staff Staff Member FABO Gold Member

      Messages:
      35,280
      Likes Received:
      17238
      Joined:
      Jan 18, 2006
      Location:
      Iowa
      Local Time:
      4:09 AM
      I
      I think I remember seeing about .040 is the max. Anything more than about .030, I would have it sconic checked.
       
    • Lelo Dart

      Lelo Dart *

      Messages:
      1,328
      Likes Received:
      324
      Joined:
      Oct 10, 2012
      Location:
      Knob Noster MO.
      Local Time:
      4:09 AM
      Have heard .030 but I went .020. I would have gone .010 but I couldn't get Magnum pistons in that size.
       
    • RustyRatRod

      RustyRatRod 30 Degrees Outta Whack FABO Gold Member

      Messages:
      48,055
      Likes Received:
      13427
      Joined:
      Jun 7, 2010
      Location:
      Georgia
      Local Time:
      5:09 AM
      I have conveniently forgotten the name but there's a well known Mopar engine shop that builds 4" plus bore 318s. Been doin it probably 30 years. Moper will remember it if he sees this.
       
      • Like Like x 1
      • RustyRatRod

        RustyRatRod 30 Degrees Outta Whack FABO Gold Member

        Messages:
        48,055
        Likes Received:
        13427
        Joined:
        Jun 7, 2010
        Location:
        Georgia
        Local Time:
        5:09 AM
        Hensley Motorsports. Dammit I nearbout burnt my brain up thinkin about that.

        They've been buildin big inch 318s for a while.
         
        • Like Like x 3
        • pishta

          pishta I know I'm right....

          Messages:
          13,721
          Likes Received:
          3449
          Joined:
          Oct 13, 2004
          Location:
          Tustin, CA
          Local Time:
          2:09 AM
          360 bores are a +.090 but 340 bores, thats a +.130, or over a 1/4 inch diameter overbore! If thin is in, they are Flynn! Now 'big inch' is more plausable with > 4.15 stroke LA cranks available now.
           
          • Thanks! Thanks! x 1
          • Tooljunkie

            Tooljunkie King of cobble/master of the broken bolt FABO Gold Member

            Messages:
            7,764
            Likes Received:
            6303
            Joined:
            Jul 22, 2017
            Location:
            Manitoba
            Local Time:
            4:09 AM
            There were some truck “premium” blocks that could be bored over.
             
          • 67Dart273

            67Dart273 Well-Known Member

            Messages:
            38,654
            Likes Received:
            6263
            Joined:
            Oct 14, 2010
            Location:
            Idaho
            Local Time:
            2:09 AM
            Let's not forget you can stroke 'em or even just start with a 5.9 and go from there!!
             
            • Like Like x 1
            • rumblefish360

              rumblefish360 so close yet so far away

              Messages:
              33,457
              Likes Received:
              5526
              Joined:
              Jun 21, 2005
              Location:
              New York, on a Island
              Local Time:
              5:09 AM
              The 318 from Hennsely gets sonic checked for a 4.00 bore.

              The 318’s cylinderwalls are only so thick. How far it goes needs a sonic check to know for sure.

              I suggest not think it can go to a 4.04/340 bore.
               
              • Agree Agree x 2
              • Dusterfreak

                Dusterfreak Well-Known Member

                Messages:
                122
                Likes Received:
                19
                Joined:
                Aug 29, 2010
                Location:
                Finland
                Local Time:
                11:09 AM
                I was looking for a 5.9 but those are rare here in finland, pickn pulls were asking 1500€, its almost 1800$ :D
                I was thinking about stroking, but that includes 0.030 overbore also and a 2000$ plus freight plus taxes so ill be in 3000$ then...
                 
              • RustyRatRod

                RustyRatRod 30 Degrees Outta Whack FABO Gold Member

                Messages:
                48,055
                Likes Received:
                13427
                Joined:
                Jun 7, 2010
                Location:
                Georgia
                Local Time:
                5:09 AM
                Well of course they do. I kinda figure some things just go without sayin. lol
                 
                • Like Like x 1
                • RustyRatRod

                  RustyRatRod 30 Degrees Outta Whack FABO Gold Member

                  Messages:
                  48,055
                  Likes Received:
                  13427
                  Joined:
                  Jun 7, 2010
                  Location:
                  Georgia
                  Local Time:
                  5:09 AM
                  3K is pretty cheap for an engine.
                   
                  • Thanks! Thanks! x 1
                  • rumblefish360

                    rumblefish360 so close yet so far away

                    Messages:
                    33,457
                    Likes Received:
                    5526
                    Joined:
                    Jun 21, 2005
                    Location:
                    New York, on a Island
                    Local Time:
                    5:09 AM
                  • 67Dart273

                    67Dart273 Well-Known Member

                    Messages:
                    38,654
                    Likes Received:
                    6263
                    Joined:
                    Oct 14, 2010
                    Location:
                    Idaho
                    Local Time:
                    2:09 AM
                    Oh, FINLAND I didn't notice your location. I'm in "the sticks" of the N end of Idaho state, and can sometimes "bitch" about the lack of used speed parts, etc. But you guys must have it ROUGH!!!
                     
                    • Like Like x 2
                    • Dusterfreak

                      Dusterfreak Well-Known Member

                      Messages:
                      122
                      Likes Received:
                      19
                      Joined:
                      Aug 29, 2010
                      Location:
                      Finland
                      Local Time:
                      11:09 AM
                      That would only be the shortblock.. add heads, cam,valvetrain and intake...
                       
                    • famous bob

                      famous bob mopar misfit

                      Messages:
                      11,242
                      Likes Received:
                      2784
                      Joined:
                      Aug 14, 2011
                      Location:
                      okla
                      Local Time:
                      4:09 AM
                      .030 , is .005 over an 1/8" -----------------------1/4" is .0250
                       
                    • RustyRatRod

                      RustyRatRod 30 Degrees Outta Whack FABO Gold Member

                      Messages:
                      48,055
                      Likes Received:
                      13427
                      Joined:
                      Jun 7, 2010
                      Location:
                      Georgia
                      Local Time:
                      5:09 AM
                      3K is pretty cheap for a short block, too.
                       
                      • Agree Agree x 1
                      • RustyRatRod

                        RustyRatRod 30 Degrees Outta Whack FABO Gold Member

                        Messages:
                        48,055
                        Likes Received:
                        13427
                        Joined:
                        Jun 7, 2010
                        Location:
                        Georgia
                        Local Time:
                        5:09 AM
                        There. I fixed your decimals. lol
                         
                        • Thanks! Thanks! x 2
                        • toolmanmike

                          toolmanmike FABO Staff Staff Member FABO Gold Member

                          Messages:
                          35,280
                          Likes Received:
                          17238
                          Joined:
                          Jan 18, 2006
                          Location:
                          Iowa
                          Local Time:
                          4:09 AM
                          :thumbsup:
                          A little zero makes a huge difference.
                           
                        • pishta

                          pishta I know I'm right....

                          Messages:
                          13,721
                          Likes Received:
                          3449
                          Joined:
                          Oct 13, 2004
                          Location:
                          Tustin, CA
                          Local Time:
                          2:09 AM
                          you wanna go +.130 (340 bore out of a 318) I was thinking radii to diameter..my bad.
                           
                        • Lelo Dart

                          Lelo Dart *

                          Messages:
                          1,328
                          Likes Received:
                          324
                          Joined:
                          Oct 10, 2012
                          Location:
                          Knob Noster MO.
                          Local Time:
                          4:09 AM
                          390 cubes with a 4" stroke
                           
                          • Agree Agree x 1
                          • Dusterfreak

                            Dusterfreak Well-Known Member

                            Messages:
                            122
                            Likes Received:
                            19
                            Joined:
                            Aug 29, 2010
                            Location:
                            Finland
                            Local Time:
                            11:09 AM
                            Now I have a plan... 0.030 over with KB 167-30 pistons, eq heads and air gap :)... Thats if water hasnt ruined two cylinders.
                             
                          • YY1

                            YY1 Well-Known Member

                            Messages:
                            5,461
                            Likes Received:
                            1228
                            Joined:
                            Oct 11, 2011
                            Location:
                            FL
                            Local Time:
                            5:09 AM
                            .040 with 4 inch is 392 IIRC and I think can go larger bore.

                            Has the OP tried honing?
                             
                          • famous bob

                            famous bob mopar misfit

                            Messages:
                            11,242
                            Likes Received:
                            2784
                            Joined:
                            Aug 14, 2011
                            Location:
                            okla
                            Local Time:
                            4:09 AM
                            thot that`s what I said ! my bad .
                             
                          • AJ/FormS

                            AJ/FormS The end is near FABO Gold Member

                            Messages:
                            15,005
                            Likes Received:
                            4150
                            Joined:
                            Jan 19, 2014
                            Location:
                            South-Central Manitoba,Canada, 900ftelevation
                            Local Time:
                            4:09 AM
                            What's the application?
                             
                          1. This site uses cookies to help personalize content, tailor your experience and to keep you logged in if you register.
                            By continuing to use this site, you are consenting to our use of cookies.