SP2P 2bbl worth the effort?

Fuel and Air Systems

  1. gliderider06

    gliderider06 Well-Known Member

    Messages:
    1,144
    Likes Received:
    177
    Joined:
    Oct 21, 2011
    Location:
    Delaware
    Local Time:
    12:35 AM
    For a stock 318 ramcharger, would a 2bbl sp2p intake be worth the effort over the stock intake? I'm contemplating on buying one for my Ramcharger like this one. 20181018_173804.jpg
     
  2. krazykuda

    krazykuda FABO Gold Member FABO Gold Member

    Messages:
    46,014
    Likes Received:
    11134
    Joined:
    Aug 20, 2007
    Location:
    Orland Park, IL
    Local Time:
    11:35 PM
    I would go with the 4 bbl version and install a Holley 600 vacuum secondary list #80457... It comes with an electric choke and calibrated for a late 60's style engine...

    Holley 4160 Aluminum Street Carburetor
     
    • Agree Agree x 1
    • rumblefish360

      rumblefish360 so close yet so far away

      Messages:
      33,469
      Likes Received:
      5512
      Joined:
      Jun 21, 2005
      Location:
      New York, on a Island
      Local Time:
      12:35 AM
      If your spending a lot of time and miles on the Hwy. it could be worth the effort. The vehicle is heavy & a aerodynamic brick.

      How is your state of tune and A/F ratio? That is where I would focus.
       
      • Agree Agree x 2
      • gliderider06

        gliderider06 Well-Known Member

        Messages:
        1,144
        Likes Received:
        177
        Joined:
        Oct 21, 2011
        Location:
        Delaware
        Local Time:
        12:35 AM
        Thanks. I already have a performer and a cast spreadbore, and a Holley 80457. It gets around 15mpg already, and I always try to improve on it. It's basically stock except for HEI ignition and dual exhaust.
        Thanks, Paul
         
      • rumblefish360

        rumblefish360 so close yet so far away

        Messages:
        33,469
        Likes Received:
        5512
        Joined:
        Jun 21, 2005
        Location:
        New York, on a Island
        Local Time:
        12:35 AM
        I think the OE 4bbl. & the Performer are about as good as it gets intake wise. If your carb is jetted to be dead on to slightly on the lean side for cruise, then that’s set. The best I can suggest after that would be a un restrictive air filter. LOL

        Exhaust wise, be it off exhaust manifolds or headers, your dual exhaust is the way to go. Muffler choice has a small effect. It can be helped (minimally) with a H or X.

        Otherthings, going on down the line would be ignition. I have found good results with the MSD 6A box and the stock distributor.

        What is your tire size and gear ratio?
         
        • Agree Agree x 2
        • Like Like x 1
        • rumblefish360

          rumblefish360 so close yet so far away

          Messages:
          33,469
          Likes Received:
          5512
          Joined:
          Jun 21, 2005
          Location:
          New York, on a Island
          Local Time:
          12:35 AM
          My first Magnum, a ‘79, had a 360 where I re equipped the 360 in the above fashion. Trap door air cleaner with a K&N filter, 600 AFB, iron intake, dual exhaust @ 2-1/4 off of the exhaust manifolds with an H pipe. The MSD fired the stock distributor.

          The rest was a stock 904 & 2.76 gears rolling on 235/60/15’s. The best I would get was 20 mpg’s on the Hwy. But I did have an aerodynamic advantage as well as a weight advantage @ 3600 lbs.

          Squeaking out more mileage out of the Ramcharger will be difficult. From where you stand now, anything you do for mileage will be minimal and small advancements. Some may not be cost effective.

          Thinner & taller tires
          Lower the vehicle
          Lock up trans
          Gear ratio change
          Lighter vehicle weight
          Less parasitic drag on the engine.
          Oh! I forgot about a cam change.
           
          Last edited: Feb 3, 2019
          • Like Like x 1
          • RedFish

            RedFish Well-Known Member

            Messages:
            22,680
            Likes Received:
            1682
            Joined:
            Sep 5, 2007
            Local Time:
            12:35 AM
            From what I have read, the sp2p intakes were simply to replace early OEM single plane intakes with dual plane intakes, 2 brl and 4 brl versions. It may not flow much better than a cast iron dual plane.
             
          • gliderider06

            gliderider06 Well-Known Member

            Messages:
            1,144
            Likes Received:
            177
            Joined:
            Oct 21, 2011
            Location:
            Delaware
            Local Time:
            12:35 AM
            So for the beast, other than timing chain and oil pump, it's untouched. Has the factory Holley 2bbl. I have a K&N air filter in the stock housing with fresh air tube hooked up to housing. Manifolds with 2-1/4" pipe run into hooked turbo mufflers and a H pipe before the mufflers. Ignition is factory electronic converted to HEI, heavy and a med-light springs. 8* initial, 36* mechanical and 54* with vacuum.
            Truck runs 3.21 gears and 31x10.50x15 tires. The old girl purrs at 62mph and actually gets better milage than my 97 Ram. Always try to improve on it, but i think I'm just about as best I'm going to get with the current set-up.
            Thanks
             
          • rumblefish360

            rumblefish360 so close yet so far away

            Messages:
            33,469
            Likes Received:
            5512
            Joined:
            Jun 21, 2005
            Location:
            New York, on a Island
            Local Time:
            12:35 AM
            Probably so. I think from here on out, it would be your own scientific experiment in the mileage search.

            I found the MSD an advantage since it is a multiple spark at low rpm. Consider this and other timing specks from the distributor. It appears you have a few degrees more than I expected. But then again, it is what ever the engine likes.

            Keep experimenting!
             
            • Agree Agree x 1
            • Garrett Ellison

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

              Messages:
              586
              Likes Received:
              319
              Joined:
              Jan 1, 2018
              Location:
              Southwest VA
              Local Time:
              12:35 AM
              The four barrel having, smaller primaries, will get superior mileage over the two barrel, especially the large pattern one. I like what what I have read about the Edelbrock StreetMaster and the Offy Dual-port, but SP2P was developed for motorhome usage and is probably going to make the most difference on mileage. Are you running an EGR? EGR would take a lot of tuning (Special distributor curve and lean cruise circuit) but I think it would yield the largest single gain. Is this your '87 and does it have 302 high swirl heads and roller lifters? Go with a Tri-Y header set to maximize your intake combination. There are some R/V specific cams that may be worth looking at to improve mileage too. Just read the rest of your posting, I imagine Rob is right, you are very close to all your going to get.
               
            • rumblefish360

              rumblefish360 so close yet so far away

              Messages:
              33,469
              Likes Received:
              5512
              Joined:
              Jun 21, 2005
              Location:
              New York, on a Island
              Local Time:
              12:35 AM
              I have a personal preference for a small primary 4bbl. on mileage searches. I have very good results with small square bores and small primary TQ’s.
               
              • Agree Agree x 2
              • gliderider06

                gliderider06 Well-Known Member

                Messages:
                1,144
                Likes Received:
                177
                Joined:
                Oct 21, 2011
                Location:
                Delaware
                Local Time:
                12:35 AM
                I've spent many many hours with the distributor, springs, limits, vacuum cans etc... maybe, an MSD is the next step.
                It has the EGR hooked up and functional. It does not have a roller cam and it has 302 heads.
                Thanks
                 
                • Like Like x 1
                • rumblefish360

                  rumblefish360 so close yet so far away

                  Messages:
                  33,469
                  Likes Received:
                  5512
                  Joined:
                  Jun 21, 2005
                  Location:
                  New York, on a Island
                  Local Time:
                  12:35 AM
                  FWIW, I didn’t mention that my Magnum was also under the states thumb of the upgrading to Ca. emissions. I had to have a working egr valve, vapor canister hooked up, catalytic converter or as in my case, 2 of them. I got them from Summit and they were a high flow design. It did pass emissions tests.

                  The otherwise stock ‘79 - 360 did keep up with stock mustands of the day.
                   
                  • Like Like x 1
                  • 383Scampman

                    383Scampman Well-Known Member

                    Messages:
                    1,169
                    Likes Received:
                    428
                    Joined:
                    Nov 24, 2013
                    Location:
                    New Hampshire
                    Local Time:
                    12:35 AM
                    Hay Rumblefish I, feel sorry that you have stupid smog laws in N.Y.. My friend up in Newburg can't get a smog because of a cat that is not available but you folks can have rusted floors and rockers . Makes no sense . Can't have a gun but can get a 9 month abortion . I moved to N.H. just because of the b.s. in southern new England .
                     
                    • Agree Agree x 1
                    • rumblefish360

                      rumblefish360 so close yet so far away

                      Messages:
                      33,469
                      Likes Received:
                      5512
                      Joined:
                      Jun 21, 2005
                      Location:
                      New York, on a Island
                      Local Time:
                      12:35 AM
                      Thanks but let’s correct something.

                      “You can have a gun in NY. Rifle or pistol “
                      It is actually easy to get one.
                      It’s the wait time & jumping through hoops that is retarded!

                      New York is not southern New England. There is no Southern New England. New York. It is the North East.

                      I agree on stupid smog laws!
                      I’m for laws that make sense, not to make money or Inconvenience people.

                      Aftermarket cats are available. As long as a cat is there and the engine passes smog is all that counts.
                       
                      • Agree Agree x 1
                      • AJ/FormS

                        AJ/FormS The end is near FABO Gold Member

                        Messages:
                        15,005
                        Likes Received:
                        4149
                        Joined:
                        Jan 19, 2014
                        Location:
                        South-Central Manitoba,Canada, 900ftelevation
                        Local Time:
                        11:35 PM
                        I think EGR got a bad rap because people didn't understand it, all that well.
                        I wouldn't retrofit it to my engine unless forced to, but I have had good success tuning with/around it. It's a Part-Throttle device and when correctly working, you should never know it's there, under load or at WOT.
                        Anybody running a long-period cam already has some to a lotta EGR at rpms up to 2000 rpm or perhaps a lil higher. Chrysler exploited this in the early years, and so were one of the last car-companies to adopt EGR hardware.
                         
                        • Like Like x 1
                        • rumblefish360

                          rumblefish360 so close yet so far away

                          Messages:
                          33,469
                          Likes Received:
                          5512
                          Joined:
                          Jun 21, 2005
                          Location:
                          New York, on a Island
                          Local Time:
                          12:35 AM
                          FWIW, The EGR valve closes with a lack of vacuum.
                          I forgot what I tested it to BUT it would be similar to going around someone on the Hwy. or getting in the Hwy. I think is was around 10 or 12 inches of vacuum.

                          Once the valve closes, it’s just like any other pre smog intake, just air and fuel running through it.
                          Magen the valve is open, it introduces exhaust which is an inert gas. This allows you to advance the timing more than without it. That is also IF you can use it or need it.
                           
                          • Agree Agree x 1
                          • Garrett Ellison

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

                            Messages:
                            586
                            Likes Received:
                            319
                            Joined:
                            Jan 1, 2018
                            Location:
                            Southwest VA
                            Local Time:
                            12:35 AM
                            And being that the exhaust partially neutralizes the fuel/air charge and increases enthalpy of the mixture, you can run a very lean cruise circuit while the EGR is on. Going with programmable EFI makes it work even better and yields larger gains, but for the cost, it better be a big difference. Affordable Fuel Injection would be my go to, all over the counter nineties ford based system.
                             
                            • Like Like x 1
                            • str12-340

                              str12-340 FABO Gold Member FABO Gold Member

                              Messages:
                              453
                              Likes Received:
                              81
                              Joined:
                              Dec 26, 2012
                              Location:
                              Vashon, WA
                              Local Time:
                              9:35 PM
                              Back to the original question. The 4bbl sp2p is great when used for its intended purpose. I've had a couple on 318 trucks and they are great for low end power, pulling a load at lower rpms. It was just what I needed in a truck that hauled firewood and building materials.
                               
                              • Like Like x 1
                              • RustyRatRod

                                RustyRatRod 30 Degrees Outta Whack FABO Gold Member

                                Messages:
                                47,992
                                Likes Received:
                                13371
                                Joined:
                                Jun 7, 2010
                                Location:
                                Georgia
                                Local Time:
                                12:35 AM
                                IMO, I don't think either one will be of much benefit. That's a heavy vehicle.
                                 
                                • Agree Agree x 1
                                • oldkimmer

                                  oldkimmer Well-Known Member

                                  Messages:
                                  9,751
                                  Likes Received:
                                  975
                                  Joined:
                                  Nov 11, 2006
                                  Location:
                                  Kindersley, Saskatchewan,
                                  Local Time:
                                  11:35 PM
                                  I had a 84 Ramchargers with a stone stock 318 2bbl. Dual exhaust. 3.21 gears. 14 miles to the gallon. 31x10.5 tires. I put in a 360 4bbl. 17 mpg. Carter Thermoquad and performer intake. Kim
                                   
                                  Last edited: Feb 10, 2019
                                  • Like Like x 2
                                  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.