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Thread: Port matching on Harmon Exhaust manifolds

  1. #1
    Mighty Thor
    When I had the Exhaust manifolds off last time I noticed that there was a lot of manifold that was not covered by the gasket. IE the exhaust port seems quite a bit bigger than the manifold hole. Can the holes safely be matched to the gasket like on the intake or is the water jacket to close, or are there other hazards? I have heard of cracked manifolds and all of the problems therefrom but I would bet there is about 1/4 inch of manifold sticking into the exhaust stream for each cylinder.

  2. #2
    Squirtin Thunder
    When I had the Exhaust manifolds off last time I noticed that there was a lot of manifold that was not covered by the gasket. IE the exhaust port seems quite a bit bigger than the manifold hole. Can the holes safely be matched to the gasket like on the intake or is the water jacket to close, or are there other hazards? I have heard of cracked manifolds and all of the problems therefrom but I would bet there is about 1/4 inch of manifold sticking into the exhaust stream for each cylinder.
    At most a little blending to inprove flow.

  3. #3
    victorfb
    they dont need to be any larger than the exhaust ports. the gaskets may just have larger holes. if the manifold matches the ports on the head leave it alone. only remove any obstructions.

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