Actually that's the second worst thing you can do. You will have heat to the bottom of the intake at all times. Not as much as if the heat riser were in the full heat position (worst thing), but exhaust will still be at the intake. What I did was put the "flapper" in the no heat position, then welded around the flapper to seal it to the exhaust manifold. I used Spray weld, but braze will work.
