Thread: mounting the column to the floor

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Originally Posted by 35fordcoupe

Bob Parmenter- do you have a picture of your exhaust flange from the engine side??

No I don't because you can't see anything. The two threaded studs were spot welded to the floor pan because I had access to that kind of welder at the time. An alternative would be to cut the head off a bolt or use some short lengths of allthread, drill a hole through the floor, weld from the outside and grind smooth. A little tricky because the floor is probably only 16 ga, but doable if you're careful. Otherwise you could weld two nuts to the exhaust flange to keep them captive and use button head bolts that would have a smooth, low profile appearance and since it's on the toe kick (if you're going through the same spot as the stocker) it's not going to be very visible.

Two other alternatives I've done just for discussion sake. One is similar to the tube thing Alan and you were talking about. In my case I was using a 1 3/4" column (though that's not particularly limiting) so I got an exhaust tip, often known as a "pencil" tip because it has that rolled end to finish it off. The 1 3/4" on the column is the OD, and the tip is made with a 1 3/4" ID to fit standard 1 3/4" exhaust pipe (though it works the same for all standard exhaust pipe dimensions). The exhaust tip is trimmed for length depending on application and welded to the floor pan (welding through the chrome plating isn't much of an issue). The nice thing about the end in the engine compartment is the rolled end acts as both a bottom stop for the column, and give a nice finished look. If you want to paint it later, bead blast it before installation to give it some "tooth". Then a set screw inside tapped through both the tip and the column to prevent rotation in addition to the upper mount. I looked through my files but don't have a clear picture of this.

The other method I used on a glass car (but would work on any sound inner structure) that I put an interior tubing support structure against the firewall. There, the column I was using was a mid '60s GM intermediate tilt unit that would slide right inside some exhaust tubing that became the exterior mast. I welded a plate near the bottom, sunk two nutserts into the tubing member and bolted it right up. That I do have a picture of. In all of these examples the carpeting hides the fasteners when finished.

As for your hole, it may be best to patch it back up and do over. What works for me is to use an undersize hole saw which gives you some leeway for drift. Then I use a carbide burr and ease the shape out to what I need for a relatively tight fit. Often, because of angle differences, the hole needs to be an ovoid shape anyway.

I've posted up the exhaust flange setup again too for those who don't recall that thread. This is also the column within exhaust tubing combo.