All small blocks share same crank ?

Small Block Mopar Engine

  1. pearljam724

    pearljam724 Member

    Messages:
    6
    Likes Received:
    1
    Joined:
    Aug 29, 2019
    Location:
    Pennsylvania
    Local Time:
    3:44 AM
    I have a 72 - 360. I’m wanting to know if all small blocks share the same crankshaft ? To my understanding the only difference the 360 has in reference to parts is a different oil pan and heads.
     
  2. pishta

    pishta I know I'm right....

    Messages:
    15,459
    Likes Received:
    5145
    Joined:
    Oct 13, 2004
    Location:
    Tustin, CA
    Local Time:
    12:44 AM
    no. 273-340 cranks are interchangeable dimensionally (67 on had a larger convertor snout), 360 cranks had larger mains and a larger rear main seal.
     
    • Like Like x 1
    • Agree Agree x 1
    • Jadaharabi

      Jadaharabi FABO Gold Member FABO Gold Member

      Messages:
      6,050
      Likes Received:
      6135
      Joined:
      Jan 8, 2016
      Location:
      Peoria, Illinois
      Local Time:
      2:44 AM
      The 360 had larger main bearings and as stated a larger rear oil seal area.
      ALL 360 factory cranks are cast.

      ALL 273, 318 and 340s use the same size main and rod bearing.

      All mopar small blocks use the same size rod bearings, 273, 318, 340 and the 360.

      The factory used both cast and forged cranks in the 272, 318 and 340s. Each had its own balance requirements.
      Yes you can use a 273 crank in a 318 or 340 but you may need to rebalance it.
      Some of the 273 &318s have a differant size on the back of the crank where the converter engages it.
       
      • Thanks! Thanks! x 1
      • Agree Agree x 1
      • Jadaharabi

        Jadaharabi FABO Gold Member FABO Gold Member

        Messages:
        6,050
        Likes Received:
        6135
        Joined:
        Jan 8, 2016
        Location:
        Peoria, Illinois
        Local Time:
        2:44 AM
        Yes differant oil pan. The rear of the pan is a differant size than the others. However later on Chrysler changed the 5.2(318) magnum to use the 5.9(360) pan.
        The heads on the early 360s were some of the same used on the low compression 340s. Some of them were 1.88 J heads.
        The windage tray used on the 360 has wider spaceing for the mounting bolt holes.
        This was Accomplished two ways. The first way was they made a separate windage tray for the 360. The second way was they slotted or oblonged the mounting bolt holes of the 340 tray so that it fits both motors.
        Because of the larger main bearings they had to move the main cap bolts farther apart.

        My list of differances

        Larger mains equals larger main bearing and a larger rear seal.
        Differant oil pan
        Differant mounting holes for windage tray
        I have also found the 360 main cap bolts to be about 1/4 onch shorter but not alway
         
        • Thanks! Thanks! x 1
        • pearljam724

          pearljam724 Member

          Messages:
          6
          Likes Received:
          1
          Joined:
          Aug 29, 2019
          Location:
          Pennsylvania
          Local Time:
          3:44 AM
          Thanks guys. I’ve been chasing a driveline vibration at 70mph. Addressed many things to no avail. Only thing I haven’t addressed yet. Is driveshaft balance and tranny mount. Which I ll do both soon. If that’s not it. The crank may be bent or out of balance. That’s the only other option left I see. But, nothing vibrates when car is in motion under 70. Does anyone sell a 360 crank new for a 72 engine ?
           
        • Ottmundr

          Ottmundr 68 Fastback

          Messages:
          4,836
          Likes Received:
          6715
          Joined:
          Oct 5, 2012
          Location:
          Sonoma
          Local Time:
          12:44 AM
          Scat Cast Crankshafts 9-360-3580-6123
          Note, this is an INTERNAL balance crank.

          Crankshafts Product Search | SCAT Crankshafts

          just put in the stuff I highlighted in green

          scat_cranshafts_75tall-e1436623469954.png

          CRANKSHAFTS SEARCH

          HomeCrankshaftsCrankshafts Product Search
          CRANKSHAFT SEARCH
          Part #:
          Short Part #:
          Series:
          Make:
          Engine: 360
          Type:
          Material:
          Rear Main Seal:
          Balance:
          Stroke: 3.58
          Rod Length:
          Rod Journal:
          PrintExcelCSVCopy

          Part # Short Part # Series Make Engine Type Material Rear Main Seal Balance Stroke Rod Length Rod Journal
          4-360-3580-6123 436010 Standard Weight Chrysler 360 Small Block Forged 4340 Steel 2-Piece Int Bal, May Req Heavy Metal 3.580 6.123 2.125
          4-360-3580-6123-2 436010-2 Pro Series Lightweight Chrysler 360 Small Block Forged 4340 Steel 2-Piece Int Bal, May Req Heavy Metal 3.580 6.123 2.125
          4-360-3580-6123-3 436010-3 Superlight Crankshaft Chrysler 360 Small Block Forged 4340 Steel 2-Piece Int Bal, May Req Heavy Metal 3.580 6.123 2.125
          9-360-3580-6123 936010 Pro Stock Chrysler 360 Small Block Cast Steel 2-Piece Internal Balance, May Require Mallory 3.580 6.123 2.125
           
          • Thanks! Thanks! x 1
          • stixx

            stixx Well-Known Member

            Messages:
            700
            Likes Received:
            463
            Joined:
            May 30, 2006
            Location:
            Southern Germany
            Local Time:
            8:44 AM
            Before you tear into the motor and change the cam have the driveshaft balanced.
            A bent crank would cause vibration at any rpm, as a crank out of balance would do it in first and second gear?
             
          • JDMopar

            JDMopar Well-Known Member

            Messages:
            2,171
            Likes Received:
            985
            Joined:
            Jan 19, 2012
            Location:
            Candler, NC/Myrtle Beach, SC
            Local Time:
            3:44 AM
            I would think if the crank was out of balance, it would vibrate at the same RPM while the car is sitting still as it does at 70mph?
             
            • Agree Agree x 1
            • 67Dart273

              67Dart273 FABO Gold Member FABO Gold Member

              Messages:
              40,304
              Likes Received:
              7966
              Joined:
              Oct 14, 2010
              Location:
              Idaho
              Local Time:
              12:44 AM
              I doubt the crank is "bent." You need to detail THE REST of your combo. What are you running for transmission? If this is a stick IT MUST use a weighted flywheel to "balance" the 360 crank, needs external weighting. Likewise you must have a 360 weighted balancer

              If you have a conventional torqueflite (and not the newer OD trans) the converter MUST have weighting welded to the front face same purpose as a stick flywheel.

              Have you been able to determine if it vibrates in park or neutral at the same RPM range as you feel at speed? That will quickly tell you if it's an engine/ balance/ transmission problem, or something else in the drive train.

              And don't discount wheels/ tires out of true/ out of balance, BOTH FRONT AND REAR
               
              • Agree Agree x 1
              • stixx

                stixx Well-Known Member

                Messages:
                700
                Likes Received:
                463
                Joined:
                May 30, 2006
                Location:
                Southern Germany
                Local Time:
                8:44 AM
                Very good point. Was chasing a vibration myself long time ago that turned out to be a rear tire out of balance...
                 
              • Jadaharabi

                Jadaharabi FABO Gold Member FABO Gold Member

                Messages:
                6,050
                Likes Received:
                6135
                Joined:
                Jan 8, 2016
                Location:
                Peoria, Illinois
                Local Time:
                2:44 AM
                Check the driveshaft for balance and straightness and the tire balance or for bent rim if running steel wheels.
                 
              • JBurch

                JBurch Well-Known Member

                Messages:
                1,761
                Likes Received:
                867
                Joined:
                Oct 17, 2009
                Location:
                Owego, NY
                Local Time:
                3:44 AM
                Also check your u-joint phasing, that could also be a possible cause of vibration, one more thing to check
                 
                • Agree Agree x 1
                • pishta

                  pishta I know I'm right....

                  Messages:
                  15,459
                  Likes Received:
                  5145
                  Joined:
                  Oct 13, 2004
                  Location:
                  Tustin, CA
                  Local Time:
                  12:44 AM
                  Hmmm.. How you gonna fix that? I'd check tires for a 70 wiggle.
                   
                  • Agree Agree x 1
                  • pearljam724

                    pearljam724 Member

                    Messages:
                    6
                    Likes Received:
                    1
                    Joined:
                    Aug 29, 2019
                    Location:
                    Pennsylvania
                    Local Time:
                    3:44 AM
                    I changed U joints. Vibrated before and after. Wheels and tires are brand new and balanced. Not the slightest slop in drive shaft front or rear. So that leaves out u joints, bushing and yoke. Tail shaft bushings usually leak when worn. No slop or leaks. Driveline doesn’t make a peep until I hit 70. Then it hums a little. I noticed no drive shaft weights when I changed u joints. So im thinking it needs balanced. Or driveshaft, possibly yoke is bent. I bought the car a year ago. It rides, drives, corners like a new car. Improved a lot of things since then. Just haven’t corrected the 70 hum. Pretty sure it’s driveshaft. I’m going to take driveshaft to a shop now that it’s winter. If that not shim rear end another 2 degrees. If no results. I don’t know.
                     
                    Last edited: Nov 10, 2019
                  • Sterling

                    Sterling Well-Known Member

                    Messages:
                    120
                    Likes Received:
                    45
                    Joined:
                    Sep 29, 2007
                    Location:
                    Pottstown,Pa.
                    Local Time:
                    3:44 AM
                    Just because the tires are new and balanced doesn't mean they are not the problem. I just worked on my friends Lexus, he said it has a thump from the rear at 80 mph. I removed the rear wheels, 1 wheel was bent, and 1 tire was bad. He just had 4 new tires installed. Both rear tires were at least 4 oz. out of balance each.
                     
                    • Agree Agree x 2
                    • JBurch

                      JBurch Well-Known Member

                      Messages:
                      1,761
                      Likes Received:
                      867
                      Joined:
                      Oct 17, 2009
                      Location:
                      Owego, NY
                      Local Time:
                      3:44 AM
                      Build a new driveshaft, or cut it apart and insure u-joints are in alignment
                       
                      • Agree Agree x 1
                      • toolmanmike

                        toolmanmike FABO Staff Staff Member FABO Gold Member

                        Messages:
                        43,027
                        Likes Received:
                        26083
                        Joined:
                        Jan 18, 2006
                        Location:
                        Iowa
                        Local Time:
                        2:44 AM
                        Only if you have a 2 piece driveshaft with a slip yoke in the middle. Trucks yes, cars no unless someone cut a yoke off and welded it back on in the wrong place.
                         
                      • pishta

                        pishta I know I'm right....

                        Messages:
                        15,459
                        Likes Received:
                        5145
                        Joined:
                        Oct 13, 2004
                        Location:
                        Tustin, CA
                        Local Time:
                        12:44 AM
                        We had 4 new tires mounted and balanced at home and drive to Utah, we experienced a vibe at 80 but it went away down at 75 (?) so when we got to St. George, we took it to the same chain and had them look at it. Both rears were out of balance and one had a broken belt (big dimple on side of new tire side wall.."uh, is this supposed to look like this?" ...Nope. Did we toss a weight too? Doubtful, as the weights were stick on's inside the rim and there was no where for them to go. So we got a new tire and a balance job under warranty. They were very nice about it too. Butter smooth on way home until we hit the crappy CA freeways, then it was just loud. We pay the most in fuel taxes but have the shittiest freeways? Oh yeah, I forgot who's running the show here for the last 30 years.....
                         
                      • JBurch

                        JBurch Well-Known Member

                        Messages:
                        1,761
                        Likes Received:
                        867
                        Joined:
                        Oct 17, 2009
                        Location:
                        Owego, NY
                        Local Time:
                        3:44 AM
                        Do we know for sure that some one has not done just that???? It's worth a check to make sure it is not the problem.
                         
                      • Jadaharabi

                        Jadaharabi FABO Gold Member FABO Gold Member

                        Messages:
                        6,050
                        Likes Received:
                        6135
                        Joined:
                        Jan 8, 2016
                        Location:
                        Peoria, Illinois
                        Local Time:
                        2:44 AM
                        I use to make pump driveshafts for tanker trucks. Would measure them, cut, put the end on, weld them, install and test.
                        We called it timing the driveshaft when you put the end on. We lined it up straight with the other end.
                         
                        • Agree Agree x 1
                        • toolmanmike

                          toolmanmike FABO Staff Staff Member FABO Gold Member

                          Messages:
                          43,027
                          Likes Received:
                          26083
                          Joined:
                          Jan 18, 2006
                          Location:
                          Iowa
                          Local Time:
                          2:44 AM
                          Exactly. and you better line the yokes up or you will get a vibration you can't balance out.
                           
                          • Agree Agree x 1
                          • Jadaharabi

                            Jadaharabi FABO Gold Member FABO Gold Member

                            Messages:
                            6,050
                            Likes Received:
                            6135
                            Joined:
                            Jan 8, 2016
                            Location:
                            Peoria, Illinois
                            Local Time:
                            2:44 AM
                            If the yokes are not lined up in effect you have a twisted driveshaft and there is no way to balance it out.
                             
                            • Agree Agree x 1
                            • 66fyssh

                              66fyssh Don't Stop Believin' FABO Gold Member

                              Messages:
                              4,425
                              Likes Received:
                              2840
                              Joined:
                              Jun 22, 2013
                              Location:
                              Northwest GA
                              Local Time:
                              3:44 AM
                              Years ago I had a very slight vibration. First thing I did was take the driveshaft to the shop. While it was there for balancing I had him replace the U-joints. He even painted it for me!!

                              No more vibration!!
                               
                              • Like Like x 1
                              • toolmanmike

                                toolmanmike FABO Staff Staff Member FABO Gold Member

                                Messages:
                                43,027
                                Likes Received:
                                26083
                                Joined:
                                Jan 18, 2006
                                Location:
                                Iowa
                                Local Time:
                                2:44 AM
                                We're getting a little off subject here but this is a good video about driveshaft phasing.
                                 
                                • Thanks! Thanks! x 1
                                • Wyrmrider

                                  Wyrmrider Well-Known Member

                                  Messages:
                                  1,926
                                  Likes Received:
                                  869
                                  Joined:
                                  Sep 5, 2016
                                  Location:
                                  los angeles
                                  Local Time:
                                  12:44 AM
                                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.