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Thread: To port or not to Port

  1. #1
    Join Date
    Jun 2005
    Location
    Way up in North Dakota
    Posts
    346

    Thumbs up

    I hope some body with more smarts can help.
    My plan is to port and polish my stock cast iron exhaust manifolds. I pulled off the right one and measured the holes. The oval holes in the manifold is about 1/16" larger all around [1/8" diameter ] than the ports in the head. My question is should I open up the head ports to match the the round gaskets and all so match the manifold holes to the gasket.
    I would only go in the head about 1/4" or less to open up the ports. I don't want to mess up the heads

    PS, My dream is to put a STS turbo on someday so I want to keep the stock manifolds.

    Thanks
    2002 GMC 1/2 ton Sierra,4WD, Xct cab, camed, mid-length headers, Nelson tune, electric rad. fan, trany cooler, Heavy 5750 lbs with topper.

  2. #2
    Join Date
    Oct 2005
    Location
    Baton Rouge, LA
    Posts
    997
    If you have the "know-how" and "can-do" attitude & ability, go for it... free mod if you can do it yourself. Free flowing without the extra restriction. Aftermarket LT headers are port matched... DO IT!
    Test-n-Tune (Nov 23, 2008) - 13.65s @ 98mph

  3. #3
    Join Date
    Jun 2005
    Location
    Way up in North Dakota
    Posts
    346
    Thanks 1BADC10, I didn't know what to do about the heads so I left them alone for the time being.
    I made all of the manifolds ports the same size but the kept the oval shape. Smoothed out most of the left side, but not the right. It has a sharper bend. Will have to make or find a flex shaft to go around the bend. Allso made the flange holes to match the exhaust pipes.
    I found a good 1/32" of rust and carbon build up inside the manifolds. When I take them off next time to finish them I hope to find someplace to powder coat the inside of the manifolds. No body in town does that.
    The manifold bolts had lock tight on them , A little anti seizer made them go in nicer.
    2002 GMC 1/2 ton Sierra,4WD, Xct cab, camed, mid-length headers, Nelson tune, electric rad. fan, trany cooler, Heavy 5750 lbs with topper.

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