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Correct Motor for 1986 Trophy hardtop-gctid553291

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    Correct Motor for 1986 Trophy hardtop-gctid553291

    I am re doing a 24 ft trophy hardtop. I bought it with a cracked block 5.7 GM and am ordering a new block with new cams from Jasper. Can anyone tell me if this motor was a option for that year? I was told that it was a 305 and last owner installed a 5.7 350. While i am redoing i want to make sure and replace with correct motor for the boat. I have good mechanic that is telling me there is no difference in a motor for a boat vs a truck. Any input would be appreciated. It has a volvo 275 outdrive that was just redone a couple years ago. We will see. Thanks for input.

    #2
    Cam, and heads . There's plenty of other marinized parts but wrong cam, head combo will not work well for marine apps.

    Comment


      #3
      "scarab63" post=553303 wrote:
      Cam, and heads . There's plenty of other marinized parts but wrong cam, head combo will not work well for marine apps.
      +1

      There are lot of guys that throw auto engines in boats. But there are many specifics that a marine engine must have that an auto/truck engine will not! Go with a marine engine.
      Dave
      Edmonds, WA
      "THE FIX"
      '93 2556 5.7 Bravo II 2.0:1 18 1/4x19 P
      (.030 over-Vortec top end-part closed cooled)
      The rebuild of my 2556 https://www.baylinerownersclub.org/f...76?view=thread
      Misc. projects thread
      https://www.baylinerownersclub.org/f...56-gctid789773

      Comment


        #4
        Thanks for the response. I think i should have put this post on the Tech questions forum. Can i move it there? if so how?

        Comment


          #5
          Send Chief Alen a PM, he can o it for ya
          Dave
          Edmonds, WA
          "THE FIX"
          '93 2556 5.7 Bravo II 2.0:1 18 1/4x19 P
          (.030 over-Vortec top end-part closed cooled)
          The rebuild of my 2556 https://www.baylinerownersclub.org/f...76?view=thread
          Misc. projects thread
          https://www.baylinerownersclub.org/f...56-gctid789773

          Comment


            #6
            "sflanery" post=553313 wrote:
            Thanks for the response. I think i should have put this post on the Tech questions forum. Can i move it there? if so how?
            Just that easy.

            Marine engines are designed to run at 3/4 to full throttle. Truck engines are not. they have brass or bronze casting plugs also
            Boatless at this time

            A veteran is someone who, at one point in their life, wrote a blank check made payable to "The United States of America," for an amount of "up to and including their life."

            Comment


              #7
              "sflanery" post=553291 wrote:
              Can anyone tell me if this motor was a option for that year? I was told that it was a 305 and last owner installed a 5.7 350. While i am redoing i want to make sure and replace with correct motor for the boat. Thanks for input.
              I would be willing to bet the 350 was an option. The 305 is likely what came standard as Bayliner has always had a tendency to under power. I would not put a 305 back in. The 350 outwardly takes up the same real-estate on the outside but with much more horsepower inside, and is a much better option. The 350 is IMO the correct engine and it should push that boat nicely.

              Comment


                #8
                Jasper builds marine engines also.

                I however i like Michigan motors.

                If rick chimes in ask him about calling MM with his specs for a " quench effect " engine.

                People you need something moved out of another forum, please contact that forums moderator.

                All the Moderators here can moderate all forums, as can the big bosses, admin.
                Be good, be happy, for tomorrow is promised to no man !

                1994 2452, 5.0l, Alpha gen. 2 drive. Sold ! Sold ! Sold !

                '86 / 19' Citation cuddy, Merc. 3.0L / 140 hp 86' , stringer drive. Sold ! Sold ! Sold !

                Manalapan N.J

                Comment


                  #9
                  Go with a 350 longblock from Michigan motorz. I was in the same boat as you (not literally) and had a 305 that needed to be replaced.

                  I bought a complete motor with new 4 barrel carb and fresh water cooling. Michigan specializes in boat motors so they know what boats need. Its not a mom and pop place that does one or two engines per year.

                  My boat came with a 305 that had 20hours on it. The previous owners "mechanic" buddy put it in. I used it for one season and it never ran very good. It got horrible mileage, struggled to get the boat on plane, wouldn't go over 4,000rpm or 32mph, and rusted to heck! So Im pretty sure it was not a marine engine.

                  Comment


                    #10
                    An auto engine will not last long in a boat!

                    My port engine is a reman Jasper marine engine,,,very happy with it
                    Joon, Kathy, Jaden & Tristan
                    Uniflite 42 AC, DD 671N
                    93 3058 sold
                    92 2855 (day boat)
                    91 Fourwinns 205 (lake boat)
                    Longbranch WA
                    Life is Good

                    Comment


                      #11
                      Thanks everyone. I just order a new motor from Michigan Motorz. Took all of your advice and got the marine motor with roller cams. I will be picking it up on the way home from a lake Erie walleye fix for a couple days next week. I will post pictures as i get it installed. Really appreciate all of the input from all of you.

                      Comment


                        #12
                        "sflanery" post=553291 wrote:
                        I have good mechanic that is telling me there is no difference in a motor for a boat vs a truck. Any input would be appreciated. It has a volvo 275 outdrive that was just redone a couple years ago.
                        This mechanic is not a true Marine Mechanic, or he'd not be telling you this.

                        While there will be subtle differences ... it will be enough to make a difference for you in the long haul.

                        It's much more than brass casting core plugs, head gaskets and camshaft profile.

                        IMO, to do this correctly, you'll need to specify which pistons willl be used. Most all rebuilders opt for the standard GM build with the full dished pistons.

                        The Full Dished pistons cannot possible offer a quench area.

                        Full dished pistons also require the ignition advance to be held back as to prevent ignition induced detonation.

                        When held back, the LPCP is also held back, resulting in less torque.

                        The quench area is needed for a true SBC Marine Engine.

                        http://www.marineengine.com/boat-for...ng at post #7.

                        It's a No Brainer.... and it won't break the boat bank to do so.

                        Any company can do this build for you if you ask for it.

                        One company out there who is willing to do a correct SBC Marine build would be Michigan Motors.... but you'll need to specify.

                        BTW.... here's what Jasper offers in the SBC. (upper image is from Jasper's web site)

                        [attachment]4959 wrote:
                        SBCfulldishedpistonNO2.jpg[/attachment]

                        Also.... since you are Volvo Penta, the Duo Prop lower unit is an option for you.

                        The DP will improve performance as greatly as though adding approx 80 horse power with your existing single prop drive.

                        A bit expesive... but worth in IMO.

                        .
                        Rick E. Gresham, Oregon
                        2850 Bounty Sedan Flybridge model
                        Twin 280 HP 5.7's w/ Closed Cooling
                        Volvo Penta DuoProp Drives
                        Kohler 4 CZ Gen Set

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