by Larry Paulick in the March 2002 RootesReview:
The Potential Problem
If your Tiger has more horsepower and torque than the standard engine, or if you have added wider tires, you should think of adding a Drive Shaft Safety Loop. The reason is that when the engine is developing lots of power, especially torque, and when the tires hook up, a lot of strain is put on the driveline. If your universal joint, especially the front one, is old or not up to the torque of your engine, it may give. Next, the driveline will be flopping around, will probably drop to the ground, and if it digs in, then your drive shaft becomes a pole vault for the car.
The Solution
The solution is a Drive Shaft Safety Loop. This is required by NHRA and IHRA, if you race, and for a good reason. Summit (www.summitracing.com) sells one that meets NHRA and IHRA requirements, is very sturdy, adjustable, and sells for around $25. It is 2″ wide, and 1/4″ thick. I put one on my Tiger, and here is what I did to fit it up.
The upper hoop is too wide to fit into the Tiger’s drive shaft tunnel. The metal was too thick for me to crush in the bench vise so I heated it with a torch until cherry red and then reduced its width until it just fit in the driveline tunnel.
The lower portion of the hoop must also be heated. I adjusted the lower hoop so that it just fit in the upper hoop. There are 4 holes already drilled in the upper and lower halves but I did not want the lower half sticking down that much, so I cut about 1″ off of it. I used the holes in the upper hoop as a template to drill new holes in the lower hoop.
The part of the bracket that bolts to the body is too wide and interferes with various parts around the front portion of the drive shaft, so I cut it to allow room near the drive shaft tunnel and to drill and bolt the shortened bracket to the body. You use the supplied nuts, bolts, and 2″ body washers to bolt the new shortened bracket to the body. 
After you tighten up the bolts, you are finished. The drive shaft can just be removed with the safety loop in place, or if you want, it is a simple matter to unbolt the lower portion of the loop.
One more safety item for your Tiger that is easy and cheap to do.