340 Build Advice

Small Block Mopar Engine

  1. Alexhetti

    Alexhetti Well-Known Member

    Messages:
    88
    Likes Received:
    29
    Joined:
    Aug 19, 2020
    Location:
    North Carolina
    Local Time:
    5:51 AM
    Hello all, I’m seeking advice on a 340 build. I have no experience building engines need some guidance on matching parts and what all will be required for the build. Im going to try and locate an experienced builder to put it together but figured it would be nice to know what I should gather before that time comes. I’ve located 2 340 blocks, one a 73 and one a 69. Both have been machined .030 over. The car it’s going in will be used mostly for street driving and some auto cross and would like it to produce around 400-500 hp. Additional, it’ll most likely be using an efi system. If you’re knowledgable in this area let me know.
     
    • Like Like x 1
    • Scody21

      Scody21 Just send it

      Messages:
      2,054
      Likes Received:
      2512
      Joined:
      Jul 17, 2019
      Location:
      Southwest Washington Coast
      Local Time:
      2:51 AM
      Here’s a few questions to ask yourself. What’s your budget? Heads and parts. Headers? What transmission, rear end and gearing, tire size, car weight.

      400 HP out of a 340 is easy, 500 is a little bit harder.

      I’m at 400 right now in my 340 duster. It is .30 over, 2.02 J heads cleaned up, not ported with comp magnum roller rockers, 10.2/1 with a comp XE285HL which is a hydro 241/247 on 110. MSD and a 750 double pumper. This a solid build for an Auto, but with a 4 speed sucks until your up on the cam. Ask me how I know.

      be prepared to spend a bunch of money if you just have a block as parts add up really fast.

      A lot of members here have the 408 from Blue Print. You can’t beat the price unless you know people to get “jobber” pricing on parts and know a machine shop that hood and cheap.
       
      • Like Like x 1
      • Agree Agree x 1
      • replicaracer43

        replicaracer43 Grumpy Old Man

        Messages:
        5,467
        Likes Received:
        5419
        Joined:
        Oct 10, 2008
        Local Time:
        4:51 AM
        Your goals are easily achieved, and it looks like your in NC? if so, and your interested, send me a PM, I am a engine builder, and I especially like helping out another mopar guy!
         
        • Like Like x 10
        • OldmanRick

          OldmanRick Well-Known Member

          Messages:
          7,226
          Likes Received:
          709
          Joined:
          May 11, 2012
          Location:
          Ladson, Sc
          Local Time:
          5:51 AM
          The 69 will have a forged crank.....that's a plus for that hp level
           
          • Like Like x 1
          • Agree Agree x 1
          • MOPAROFFICIAL

            MOPAROFFICIAL FABO Gold Member FABO Gold Member

            Messages:
            11,707
            Likes Received:
            11290
            Joined:
            Jun 1, 2016
            Location:
            Oceanside ca.
            Local Time:
            2:51 AM
            Imo you need gears.Only good with auto and 3200+ stall is more like it.
             
            • Like Like x 1
            • Agree Agree x 1
            • Garrett Ellison

              Garrett Ellison Amateur driver on public roadway, do not imitate.. FABO Gold Member

              Messages:
              4,636
              Likes Received:
              3873
              Joined:
              Jan 1, 2018
              Location:
              Southwest VA
              Local Time:
              5:51 AM
              Go to Replicaracer43 and make full use of an experienced engine builder. There’s so much to take in consideration that separates a so-so engine (or a time bomb!) and one that runs as good as you like and meets your target goals. I’m all on board with the stroker crank for 500hp and auto crossing.
               
              • Like Like x 1
              • Agree Agree x 1
              • MOPAROFFICIAL

                MOPAROFFICIAL FABO Gold Member FABO Gold Member

                Messages:
                11,707
                Likes Received:
                11290
                Joined:
                Jun 1, 2016
                Location:
                Oceanside ca.
                Local Time:
                2:51 AM
                Use the 69 crank and rods in the 73 block.

                Promax or trick flow for a good ootb head
                A solid cam in the realm of..250's@.050 dur .560 or so lift 108lsa intake 286 or so dur.

                Or solid roller.
                 
                Last edited: Feb 4, 2022
                • Like Like x 1
                • OldmanRick

                  OldmanRick Well-Known Member

                  Messages:
                  7,226
                  Likes Received:
                  709
                  Joined:
                  May 11, 2012
                  Location:
                  Ladson, Sc
                  Local Time:
                  5:51 AM
                  Did'nt catch he said "blocks" if the're empty the skies the limit...lol
                   
                  • Like Like x 2
                  • K.O. SWINGER

                    K.O. SWINGER Meeting in the alley since 1976

                    Messages:
                    2,806
                    Likes Received:
                    2746
                    Joined:
                    Nov 18, 2010
                    Location:
                    oregon
                    Local Time:
                    4:51 AM
                    As mentioned a 400 horsepower 340 is fairly easy but 500 the price goes up quite a bit along with the RPM range and the street ability heads the other direction. a little more manageable with a four-speed. A 500 horsepower 340 is awesome but it ain't cheap.
                     
                    • Like Like x 1
                    • Agree Agree x 1
                    • BA388

                      BA388 Member

                      Messages:
                      6
                      Likes Received:
                      6
                      Joined:
                      Dec 29, 2021
                      Location:
                      Minnesota
                      Local Time:
                      4:51 AM
                      I think I would go 4.00” stroke crank and flat top pistons with tight quench.
                       
                      • Agree Agree x 2
                      • Like Like x 1
                      • Scody21

                        Scody21 Just send it

                        Messages:
                        2,054
                        Likes Received:
                        2512
                        Joined:
                        Jul 17, 2019
                        Location:
                        Southwest Washington Coast
                        Local Time:
                        2:51 AM
                        Right. With a 4 speed, 3.91’s and short tires it no slouch, but the changing I’m working on it’s going to be beast.
                         
                        • Like Like x 1
                        • K.O. SWINGER

                          K.O. SWINGER Meeting in the alley since 1976

                          Messages:
                          2,806
                          Likes Received:
                          2746
                          Joined:
                          Nov 18, 2010
                          Location:
                          oregon
                          Local Time:
                          4:51 AM
                          Okay I dig the stroker crankshaft suggestions but then it's not really a 340 it's a 416 or whatever, if that's what the OP Wants then that's cool but I thought he was talking about a 340ish =stock stroke cubic inch motor.
                           
                          • Like Like x 2
                          • Agree Agree x 2
                          • K.O. SWINGER

                            K.O. SWINGER Meeting in the alley since 1976

                            Messages:
                            2,806
                            Likes Received:
                            2746
                            Joined:
                            Nov 18, 2010
                            Location:
                            oregon
                            Local Time:
                            4:51 AM
                            Sounds like my setup LOL
                             
                            • Like Like x 1
                            • ou812

                              ou812 Well-Known Member

                              Messages:
                              1,514
                              Likes Received:
                              465
                              Joined:
                              Jan 15, 2005
                              Location:
                              SoCal
                              Local Time:
                              2:51 AM
                              Find your builder first...the ask HIM what he would like for parts...not the other way around.
                               
                              • Agree Agree x 4
                              • Like Like x 1
                              • Alexhetti

                                Alexhetti Well-Known Member

                                Messages:
                                88
                                Likes Received:
                                29
                                Joined:
                                Aug 19, 2020
                                Location:
                                North Carolina
                                Local Time:
                                5:51 AM
                                As far as budget, I'm not entirely sure because I really don't know an average for a build. I know I've seen people saying they've spent anywhere from 5k to 20k on an engine build. I have funds available for the process, however. Currently, I have a 904 trans that I'm considering switching to a 4-speed or 727 (haven't decided), 1 5/8 TTI headers, 8 3/4 rear with 3.55 gears, 27" tires 15x8 in the back and 15x6 front, also considering moving to 18's.

                                My main thing is I don't have the knowledge to match parts to what I would like an engine to achieve. Like I said, mainly a strong runner driver with occasional autocrossing.
                                 
                                • Like Like x 1
                                • Alexhetti

                                  Alexhetti Well-Known Member

                                  Messages:
                                  88
                                  Likes Received:
                                  29
                                  Joined:
                                  Aug 19, 2020
                                  Location:
                                  North Carolina
                                  Local Time:
                                  5:51 AM
                                  That makes sense for sure.
                                   
                                • Alexhetti

                                  Alexhetti Well-Known Member

                                  Messages:
                                  88
                                  Likes Received:
                                  29
                                  Joined:
                                  Aug 19, 2020
                                  Location:
                                  North Carolina
                                  Local Time:
                                  5:51 AM
                                  I'm definitely not against a stoker. My car is not stock in any way so I don't really care about correctness. I'd just like a fast, fun, and dependable engine. Currently, my car has a tired '78 360 in it with a mild cam in it. It kinda seems to have just been thrown together by someone who didn't know what they were doing (among other things in the car). I have no previous history of its build or what all was done to it and I'd prefer to have an engine built so that I know exactly what's been done and it works for my setup.
                                   
                                • Alexhetti

                                  Alexhetti Well-Known Member

                                  Messages:
                                  88
                                  Likes Received:
                                  29
                                  Joined:
                                  Aug 19, 2020
                                  Location:
                                  North Carolina
                                  Local Time:
                                  5:51 AM
                                  Thank you sir! I'll send you a pm
                                   
                                  • Like Like x 1
                                  • Alexhetti

                                    Alexhetti Well-Known Member

                                    Messages:
                                    88
                                    Likes Received:
                                    29
                                    Joined:
                                    Aug 19, 2020
                                    Location:
                                    North Carolina
                                    Local Time:
                                    5:51 AM
                                    Agreed, I just sent him a pm
                                     
                                    • Like Like x 2
                                    • OldmanRick

                                      OldmanRick Well-Known Member

                                      Messages:
                                      7,226
                                      Likes Received:
                                      709
                                      Joined:
                                      May 11, 2012
                                      Location:
                                      Ladson, Sc
                                      Local Time:
                                      5:51 AM
                                      For street and autocross with the 3.55's, i'd look for torque in the 3500/4000 rpm range. How much & how you get there depends on engine size and budget. I personally would prefer the 4spd for what you want to do.
                                       
                                      • Like Like x 1
                                      • Agree Agree x 1
                                      • Scody21

                                        Scody21 Just send it

                                        Messages:
                                        2,054
                                        Likes Received:
                                        2512
                                        Joined:
                                        Jul 17, 2019
                                        Location:
                                        Southwest Washington Coast
                                        Local Time:
                                        2:51 AM
                                        the 904 is plenty strong for 5-600 I'd run it before buying a 727. But a 4 speed is king. The gearing, tire setup you have is good. Would not mess with it.

                                        as for budget, you can figure 10 grand is a solid number as the cost of things just keeps rising. A stroker crank set up is around 2 grand. Machining about 2K, 2K in labor, there’s 6. Add 2K for heads, 1000 for rockers, lifters, push rods, 500 for a carb, 500 for MSD, 500 for water pump, alt, starter, shit adds up quick….. did not even get to the 4 speed swap yet…
                                         
                                        Last edited: Feb 4, 2022
                                        • Agree Agree x 2
                                        • Like Like x 1
                                        • Alexhetti

                                          Alexhetti Well-Known Member

                                          Messages:
                                          88
                                          Likes Received:
                                          29
                                          Joined:
                                          Aug 19, 2020
                                          Location:
                                          North Carolina
                                          Local Time:
                                          5:51 AM
                                          One of the main reasons I'm thinking about changing trans is because the 904 appears to be original to the car and definitely needs a rebuild. Also the converter definitely isn't sized correctly for the current engine so I'll need to be buying one anyways. I'd prefer to have a 4 speed just for the experience if anything.

                                          With the budget, I figured I'd be looking at around 1ok for a build, which I'm okay with. The car needs a new engine one way or another and I prefer to put the money into building something good rather than just a rebuild of the 360. Thank you for the info.
                                           
                                        • MOPAROFFICIAL

                                          MOPAROFFICIAL FABO Gold Member FABO Gold Member

                                          Messages:
                                          11,707
                                          Likes Received:
                                          11290
                                          Joined:
                                          Jun 1, 2016
                                          Location:
                                          Oceanside ca.
                                          Local Time:
                                          2:51 AM
                                          10k engine?
                                          Wheres the other 5 grand going once the motor is done?

                                          Lol
                                           
                                          • Like Like x 2
                                          • Agree Agree x 1
                                          • Garrett Ellison

                                            Garrett Ellison Amateur driver on public roadway, do not imitate.. FABO Gold Member

                                            Messages:
                                            4,636
                                            Likes Received:
                                            3873
                                            Joined:
                                            Jan 1, 2018
                                            Location:
                                            Southwest VA
                                            Local Time:
                                            5:51 AM
                                            Upgrading the 904 to a 998 or an 999 (2.47 1st and 1.55 second) with six thin clutches in place of 5 with a custom converter and a Trans-Go TF3 manual valve body kit would make it perform like you want. It's the route I would take if I kept it at a stock stroke. 3.58 inch stroke is also a good option for 367-379 inch combination. I do like a four speed for auto cross though.
                                             
                                          • fishmens67

                                            fishmens67 FABO Gold Member FABO Gold Member

                                            Messages:
                                            13,159
                                            Likes Received:
                                            14658
                                            Joined:
                                            Nov 10, 2012
                                            Location:
                                            idaho
                                            Local Time:
                                            4:51 AM
                                            Are you not wanting any money for your labor and machine work ? I see at least 5 grand in parts for a running 500 HP engine.
                                             
                                            • Like Like x 1
                                            • Agree Agree x 1
                                            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.