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Repowering 1987 Cobra 2250, Q= Centre riser to OMC Y-pipe-gctid344179

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    Repowering 1987 Cobra 2250, Q= Centre riser to OMC Y-pipe-gctid344179

    Hello

    I have aluminium manifold and 4" riser`s from GLM as I should fit to a OMC Cobra outdrive(motor 5,7 86-with the orginal volvo-penta closed cooling L-shaped, half sys.).

    Question is witch type elbow should I use to conect to my Y-pipe? Any one done this conversion?

    Thanks Torsa

    #2
    HI a frend of mine has a 89 2455 with an omc 5.7 he fitted mercrusier center rise manifolds and used the standard omc elbow as for yore closed water cooling im sure it will work.

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      #3
      When I converted mine over to center riser, I used these pipes from Moore Performance - http://www.ebay.com/itm/OMC-COBRA-VO...item48359c00c6 . Port side fits perfect, and the starboard side required some trimming off the upper edge (like 3" or so). They get very hot, so I wrapped them with header insulation wrap. The manifolds I have are this style - http://www.ebay.com/itm/CHEVY-V8-305...item484330fc51 .

      At the time I did this a couple years ago, I couldn't find anything else that would work to adapt the OEM Y-pipe to the center riser.

      It is possible that these may be usable as well - http://www.ebay.com/itm/V6-EXHAUST-P...item2559999564 . But, they may be the wrong dia. on the outlet. Dennis may know, but he was basically confused on my situation and wasn't really much help at the time.

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        #4
        When I did mine I used a mix of OMC and Merc elbows and shortened one end and lengthened the other.Unless you have a TIG and the time it's not much of an option for you but that was the best option I had.I looked in Dennis Moore's warehouse and those stainless ones wouldn't help me, he even commented that guys had been complaining about the heat issue so now he is making them with aluminum.These are the style elbows I used,http://www.ebay.com/itm/Pair-OMC-Cob...item588fced84eI had to cut off the inlet end and increase the diameter and weld on 4" tubes (cut off a pair of merc elbows) to match the risers. I welded the pieces removed, 3.5" dia, to the outlet end so they would reach the y pipe.Also, mine is a Ford so I realize it's a bit of apples and oranges, just some FYI.

        [img]/media/kunena/attachments/vb/647424=23859-DSC02238.jpg[/img]
        " WET EVER "
        1989 2459 TROPHY OFFSHORE 5.8L COBRA / SX
        mmsi 338108404
        mmsi 338124956
        "I started with nothing and still have most of it left"

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          #5
          Thanks to all of you:worth

          This is what I found: Link to ebasic power

          http://bpi.ebasicpower.com/pc/GLM50780/OMC8B

          I have found out that the riser down angle is 7 degree.

          At tis time I have used 9k $ on resturation

          Regards Torsa

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