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Thread: Fast Fred's Secrets of the OMC MOD50's Thread #1

  1. #51
    David_L6
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    Quote Originally Posted by David_L6
    I'm not sure how good an oval course race motor it would make with full port height and 1:1 gear ratio....... Can always raise the ports later. Can't lower them though.
    Quote Originally Posted by Mark75H
    True, but even the most extreme factory Mod 50 was an oval course racer
    Yeah, I know..... It had something like a 13:17 gear ratio though.... To be perfectly honest I don't know what port timing would be best. I do know that I can't lower them though....

    If Quincy were still in business and new pistons and rings for the Merc were still available from Mercury, I'd have Quincy pad a block, copy my 44's port timing, and see if I could run with 'em with a Mercury.

  2. #52
    David_L6
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    Quote Originally Posted by Mike Schmidt
    Full tilt Mod 50 porting worked just fine on our FRR motor 20 something years ago. Big old flat deck Desilva with two guys in it.

    There is at least one FEH out there with full Mod 50 porting. He runs better than most....

    Michael D-1

    Hhhmmmm....... (the gears are grinding now......) What would you do Mike?

  3. #53
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    hear we see a 19s with cast in liners, and we see some work on exhaust ports of one and three,
    and what are thay doin that for?
    Last edited by Fast Fred; 01-18-2006 at 04:13 PM.

  4. #54
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    this is ware thay are tryin to go, not number two cuz of heat, i'm thinkin.

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    the "straight in" case can dump heat far better than the castin liners

  6. #56
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    Originally Posted by Mike Schmidt
    Full tilt Mod 50 porting worked just fine on our FRR motor 20 something years ago. Big old flat deck Desilva with two guys in it.
    was you usein gas back then?

  7. #57
    David_L6
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    Quote Originally Posted by Fast Fred
    hear we see a 19s with cast in liners, and we see some work on exhaust ports of one and three,
    and what are thay doin that for?
    I wonder just how many different port styles were tried on those motors.... That's the second time I've seen that port style, the block that I had looks almost like a fishing motor except the timing is different, and then there's the style that the 31M block had.....
    Last edited by David_L6; 01-19-2006 at 04:02 AM.

  8. #58
    David_L6
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    About running the Mod 50 port timing in FE/SE.......... The Mod 50 had better breathing than what the FE/SE motors are allowed. Seems to me that all the RPM potential of the port timing isn't going to mean much if the reed cages and/or carbs don't flow enough to support the RPM's of the higher port timing.

  9. #59
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    air speed is way up, with single carbs, out the shoot, she should pull
    Big to the turn think that thats the same port map for the last powerhead, spun about a buck 80, thare is still more

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    Default Mod 50

    Fred, the block you show the picture of was modified that way because the port rib cracked and that was the only way to try to salvage the block. This is not an ideal situation and will most likely be the cylinder which fails. This does not accomplish the same performance as the straight in blocks. Those ports are very different and can not be duplicated by grinding on a 19S block. The reeds (4 per side) used were V4 boxes with machined openings and later style V4 stops. The Straight In had special cast reed boxes (5 per side) and matching stops.

    David L6, the Mod 50 porting requires an exhaust system which is matched to the port timing. Without the correct exhaust the higher ports will just hurt your bottom end with little help at the top. Note the ports are chamfered from the basic port section to the timing edge. This was done to maintain as much bottom end power as possible and still perform well at higher rpm.

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