Performance Enhancements for a 318

General Mopar Tech Discussions

  1. 68Coronet500!

    68Coronet500! Active Member

    Messages:
    26
    Likes Received:
    10
    Joined:
    Feb 2, 2021
    Location:
    Southern California
    Local Time:
    11:44 AM
    I'm trying to beef up my 318 and looking to start with headers unless anyone has a better idea. I'm not looking to build a race car but would certainly like more power than the stock 318 in my Coronet and am looking for some suggestions.

    I checked Jegs and they make an exhaust kit for a B Body that runs at 2.5 inches at the outflow and it's leveraging hooker headers. I also see that hooker makes another model with a 3 inch outflow, which do you think best fits what I'm trying to accomplish?

    Once that is completed, what suggestions do you have for increasing the power while keeping it out of a shop for extended periods of time?
     
    • Disagree Disagree x 1
    • Roger63

      Roger63 Well-Known Member

      Messages:
      3,516
      Likes Received:
      5083
      Joined:
      Aug 7, 2013
      Location:
      Skiatook ok
      Local Time:
      1:44 PM
      More cubic inches, seriously I had the same dilemma. Once I started the pricing of small block performance parts I discovered I can go big block for less money.
       
      • Agree Agree x 1
      • 68Coronet500!

        68Coronet500! Active Member

        Messages:
        26
        Likes Received:
        10
        Joined:
        Feb 2, 2021
        Location:
        Southern California
        Local Time:
        11:44 AM
        seems that everyone I talk to in Southern California wants a small fortune to do an engine replacement. the other issue is that it will take extended period of time for being in the shop and I'm not really into that either.
         
        • Thanks! Thanks! x 1
        • 66 Sat

          66 Sat Well-Known Member

          Messages:
          1,065
          Likes Received:
          1831
          Joined:
          Apr 26, 2015
          Location:
          Australia
          Local Time:
          1:44 PM
          Cheap set of headers into dual exhaust, 4 barrel 600 cfm carb, Edelbrock Performer or similar intake manifold and a new camshaft. Maybe 3.55 rear end.
          That should wake it up a fair bit. Do the heads further down the track if your not satisfied with the above.
           
          • Agree Agree x 2
          • Like Like x 1
          • Darter6

            Darter6 FBBO Gold Member FBBO Gold Member

            Messages:
            4,981
            Likes Received:
            5446
            Joined:
            Dec 29, 2009
            Location:
            Nevada
            Local Time:
            1:44 PM
            Pros & Cons. I'm the kinda guy that says use what ya got.
            Yes you can do allot with a 318 and it will run like a scared rabbit.
            All it take is time and money. Intake, carb, headers and exhaust are a good start.
            3'' exhaust is not a good idea with a small displacement engine. Not on a street car.You will kill performance.
            Next is what gearing do you plan on using or what do you have? 3.23 is a good all around street car gearing.
            From there the sky is the limit.
             
            • Agree Agree x 2
            • 68Coronet500!

              68Coronet500! Active Member

              Messages:
              26
              Likes Received:
              10
              Joined:
              Feb 2, 2021
              Location:
              Southern California
              Local Time:
              11:44 AM
              Thanks Darter. Sounds like I'm on the right track if I'm not going full replacement.
               
            • DeltaV

              DeltaV Endeavor to persevere FBBO Gold Member

              Messages:
              11,896
              Likes Received:
              32885
              Joined:
              Jul 11, 2015
              Location:
              Black water creek
              Local Time:
              2:44 PM
              Last edited: Apr 13, 2021
              • Agree Agree x 1
              • Roger63

                Roger63 Well-Known Member

                Messages:
                3,516
                Likes Received:
                5083
                Joined:
                Aug 7, 2013
                Location:
                Skiatook ok
                Local Time:
                1:44 PM
                Not really, since you already have a running car finding and building the engine you want as finances allow is also a choice. Your car will still be drivable while you build.
                 
              • 493 Mike

                493 Mike FBBO Gold Member FBBO Gold Member

                Messages:
                3,505
                Likes Received:
                3907
                Joined:
                Dec 25, 2011
                Location:
                White Cloud, MI
                Local Time:
                2:44 PM
                Smaller turbo. Ask DVW.
                Mike
                 
              • Tman100

                Tman100 Well-Known Member

                Messages:
                77
                Likes Received:
                128
                Joined:
                Mar 7, 2021
                Location:
                Morden MB
                Local Time:
                1:44 PM
                I’ve got a 78 318 in a 66 polara. It’s stock except for a mopar performance purple cam and some port matching to the heads. I’ve got a 360 4bbl intake on it with port matched stock iron heads. Aim running a thermoquad but I’ve run hollys and edlebrocks also. That little engine moves that 4200lb car very well. Put some timing in the 318. A good starting point is 12 degrees idle, 34 all in mechanical advance and 52 degrees all in vacuum. Car with 2.94 gears get 18 mpg at 70 mph all day long and is a force to be reconed with when it kicks into 2nd at 65mph. Don’t give up just cause you’ve got small cubes. Turn it faster... mine turns over 7500 rpm and really pulls... this is coming from a guy with a 500hp 440 also. Cam and valve springs... don’t over cam the little 318 and it will really wake up. Lots of timing and good valve springs. Tuning is key!
                 
              • 68Coronet500!

                68Coronet500! Active Member

                Messages:
                26
                Likes Received:
                10
                Joined:
                Feb 2, 2021
                Location:
                Southern California
                Local Time:
                11:44 AM
                Appreciate the insights. I don't have the technical competency or equipment to handle it on my own but am meeting with a mechanic in a few weeks and will see how capable he is on the tuning front.
                 
              • Frank Mopar

                Frank Mopar Well-Known Member

                Messages:
                877
                Likes Received:
                1372
                Joined:
                May 7, 2015
                Location:
                Buffalo, NY
                Local Time:
                2:44 PM
                If you want instant seat of the pants feel as cheap as possible, install lower gears in the rear end. IMHO
                 
              • Master Gunner

                Master Gunner FBBO Gold Member FBBO Gold Member

                Messages:
                80
                Likes Received:
                81
                Joined:
                Mar 17, 2018
                Location:
                Frost Bite Falls, Mn
                Local Time:
                1:44 PM
                Nobody seems to have mentioned the torque converter. Waking a engine up is a combination of intake, exhaust, cam, gearing, and TQ (in a auto).

                Mark
                 
              • YY1

                YY1 Well-Known Member

                Messages:
                17,925
                Likes Received:
                9966
                Joined:
                Jun 26, 2010
                Location:
                FL
                Local Time:
                2:44 PM
                Duals in 2.25 or 2.5"

                Headers may be more pain than gain unless you get $700+ TTI, Dougs, or Hooker Super Comps.

                Small 4 barrel and the aforementioned Performer intake.

                Maybe a small modern, "RV" type cam like the comp 256 or Lunati equivalent.
                 
                Last edited: Apr 14, 2021
                • Agree Agree x 1
                • YY1

                  YY1 Well-Known Member

                  Messages:
                  17,925
                  Likes Received:
                  9966
                  Joined:
                  Jun 26, 2010
                  Location:
                  FL
                  Local Time:
                  2:44 PM
                  If it has 2.76 gears, one step to 2.94 or 2 steps to 3.23 will be noticeable but not require a converter change nor will the cam family listed above.

                  ...add a sure grip while you're in there.
                   
                • Master Gunner

                  Master Gunner FBBO Gold Member FBBO Gold Member

                  Messages:
                  80
                  Likes Received:
                  81
                  Joined:
                  Mar 17, 2018
                  Location:
                  Frost Bite Falls, Mn
                  Local Time:
                  1:44 PM
                  Gears are great, but you need to know how, or know someone who knows how to set them up correctly. The OP stated that he did not have technical knowledge or equip.

                  Mark
                   
                • toolmanmike

                  toolmanmike Moderator Staff Member FBBO Gold Member

                  Messages:
                  5,784
                  Likes Received:
                  9663
                  Joined:
                  Aug 11, 2010
                  Location:
                  Iowa
                  Local Time:
                  1:44 PM
                  A 4 barrel and intake, a nice dual exhaust and a performance curve for your distributor will do some good. (@HALIFAXHOPS) The next step would be taking the engine apart, raising the compression, bigger cam, headers, and performance heads. To make that all work well you will need a higher stall torque converter and different rear gears. Speaking of gears, changing from a 2.76 to a 3.23 or 3.55 is a nice change in performance.
                   
                  Last edited: Apr 14, 2021
                  • Agree Agree x 1
                  • HALIFAXHOPS

                    HALIFAXHOPS MSGT(ret) and MOPAR only distributor rebuilder! FBBO Gold Member

                    Messages:
                    3,699
                    Likes Received:
                    1725
                    Joined:
                    May 5, 2016
                    Location:
                    Halifax, PA USA
                    Local Time:
                    2:44 PM
                    The right curve in your distributor is a great improvement to start with.
                     
                    • Agree Agree x 3
                    • 66Satellite47

                      66Satellite47 FBBO Gold Member FBBO Gold Member

                      Messages:
                      5,004
                      Likes Received:
                      4065
                      Joined:
                      Jan 15, 2015
                      Location:
                      St Paul MN
                      Local Time:
                      12:44 PM
                      Headers with 2 1/2 exhaust, a 4bbl with 600ish carb will do wonders. After that a gear change 3.23 or maybe 3.55 and then a good quality converter will amaze you.
                       
                      • Agree Agree x 1
                      • Darter6

                        Darter6 FBBO Gold Member FBBO Gold Member

                        Messages:
                        4,981
                        Likes Received:
                        5446
                        Joined:
                        Dec 29, 2009
                        Location:
                        Nevada
                        Local Time:
                        1:44 PM
                        Like I said, the sky is the limit !! More than anything have fun,You will learn allot here.
                         
                        • Agree Agree x 1
                        1. This site uses cookies to help personalise 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.