[Adger Smith]

Yes it is, same type of joint too. (nice picture) My car had been in a well know shop for some up dates and I assume a minimum wage employee had put that part of it back together. The receiver groove in the male shaft of the rack was missed by the set screw in the female part of the joint. The sad part is it looked ok when I inspected the car. The set screw was just tight on a spline, Not in it's proper location, the receiver groove. After about 50 runs of wheelstanding & my pushing & pulling on the steering wheel it worked it's way off the shaft. I still think it came off during the wheelstand at the start of the run. At the finish line when I touched the brakes, trying to slow down to keep from breaking out, It made a hard turn to the left. I was out of control, just along for the ride. (read that: crash @ 145 MPH instead of ride!)
I think the best way to secure them is by drilling and inserting a hollow roll pin and then safety wire through the center of the roll pin. That is in addition to the set screw. That is a positive method that can be visually inspected for failure. Think about it. You can't tell if those set screws are where they belong or even tight with out putting a wrench on them. The pin method and safety wire can be visually inspected. If the pin starts to loosen and slide out the wire catches it. If the pin shears off it could snap the safety wire and alert a keen eye of a pending problem. My replacement roadster has already been built.(now if I can just talk my wife into letting me race it) It has the steering secured by bolts & roll pins with safety wire. Keep an eye on things, your life could depend on it. Tim, you have a very unsafe situation. Are you sure the rack isn't at fault? The worm gear gould be slipping on the shaft or the rack could be worn out. I think I would be taking some things apart and inspecting them if that was my ride.