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  • Dear Community Members,

    Updated 9/29/20 - Upgrades have been pushed until 10/7/20

    Over the last two years, there have been updates to the environment that have introduced challenges in usability, performance, and security. Efforts to improve the technology, user interface and site performance have revealed weaknesses in the platform and outdated software our site uses. This has made it increasingly difficult and frustrating to support and upgrade to more modern reliable standards that users deserve. This is not the experience we want for the members of this community.

    Members want a fast site that performs well across all devices, to be able to find relevant and interesting content, and easily share through text, images, video, and messaging on a secure platform. Our goal is to provide this user experience to all members. We will be updating to a new platform to better meet the needs of this community and allow us to provide support more efficiently. Our focus is to create a sustainable platform that performs well and loads faster on all devices while offering seamless ways to search and connect. Technology is constantly innovating - by creating an environment that we control we can maintain the site with more frequent improvements and maintenance updates.

    Although change can be difficult, we are here to support you through the process. We make every effort to review existing settings and make the changes needed so the migration goes smoothly. If you notice something doesn’t seem correct once the site goes live, don’t panic! We’ll have a dedicated person monitoring as the site goes live to answer any questions and provide support through this change.

    What’s next?
    When will this be happening? The plan is to put our current forums into maintenance mode (off line) at around 9am MST on 10/7/2020! The whole transition should take 30-36 hours. We recognize the user experience is slow and there are bugs from the outdated software. The sooner we can change that the better we can make the experience for you. You’ll start to see activity related to cleanup in preparation for migration very shortly. We will post an announcement to the community prior to starting the actual data migration.

    We appreciate each member’s contribution to this community and look forward to an improved experience for you all.

    - Management

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4.3 MPI vs. Carb

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  • 4.3 MPI vs. Carb

    So my 4.3 MPI Vortec has a cracked block and I need to build a new motor. What's the HP difference if I go back to basics with a carb engine? I know I'll need a distributor, carb and intake manifold and lots of wiring mods. Anything else that I have to change? If I use flat top pistons in carb or MPI build will it run on regular gas?

  • #2
    Just out of curiosity, why would you rather build a carb-ed engine instead of an MPI? My 4.3 is carb-ed, and I wish it were MPI...
    If you do go carb-ed, at least go 4bbl instead of 2bbl.

    Comment


    • #3
      2bbl 190HP, 4bbl 205HP, MPI 220HP

      Unless your going to build some real power, just get a stock vortec motor and put your stuff back on it
      94 Formula 27PC Custom 509MPI MEFI3 , B3 XR
      95 Rinker 232 w/ 7.4L Carb 0F425011 B1 0F486471
      07 Seadoo GTX
      Merc Adults Only VP Adults Only
      G-Dad always said "First Liar doesn't stand a chance"

      Comment


      • #4
        the carb'd vortec 4.3 was near the edge of reversion and detonation, the MPI vortec 4.3 is on the ragged edge because the ECM can back off the timing as needed.

        I would simply put a new or re-man long-block back under your MPI stuff.
        Last edited by Scott Danforth; September 16th, 2020, 06:34 AM.
        Cheesehead boating the Gulf Coast of FLA 27.51° N, 82.53° W

        1988 Cruisers Rogue 2420 -VP 290 DP now powered by custom 468 - https://forums.iboats.com/forum/owner...988-rogue-2420

        Past Boats
        1970 Wooster Hellion - Merc 9.8
        2002 SeaRay 190BR - 5.0 - A1G2 - "Cheeseheads in Paradise"
        1984 Avanti 170DLI -3.0 stringer- "Ship Happens"

        What’s behind you doesn’t matter.Enzo Ferrari

        Comment


        • #5
          Originally posted by alldodge View Post
          2bbl 190HP, 4bbl 205HP, MPI 220HP

          Unless your going to build some real power, just get a stock vortec motor and put your stuff back on it
          OK that makes sense. I figured I'd find a core and build my own long block since I've done a few engines before. Would I be able to run flat top pistons on regular gas?

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          • #6
            Haven't rebuilt a SBC since the 80's only BBC. Most use dish pistons with the standard rebuild. Scott Danforth
            94 Formula 27PC Custom 509MPI MEFI3 , B3 XR
            95 Rinker 232 w/ 7.4L Carb 0F425011 B1 0F486471
            07 Seadoo GTX
            Merc Adults Only VP Adults Only
            G-Dad always said "First Liar doesn't stand a chance"

            Comment


            • #7
              Sign up today
              factory GM Boat/Truck/Generator/Trash-pump engines are flat top with 4-reliefs

              just build it stock so you dont have to re-program. if you change the combustion mix (CR, cam profile, etc) , you need to re-program the ECM.
              Cheesehead boating the Gulf Coast of FLA 27.51° N, 82.53° W

              1988 Cruisers Rogue 2420 -VP 290 DP now powered by custom 468 - https://forums.iboats.com/forum/owner...988-rogue-2420

              Past Boats
              1970 Wooster Hellion - Merc 9.8
              2002 SeaRay 190BR - 5.0 - A1G2 - "Cheeseheads in Paradise"
              1984 Avanti 170DLI -3.0 stringer- "Ship Happens"

              What’s behind you doesn’t matter.Enzo Ferrari

              Comment

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