N H R A rules state that the loop must be installed no more than 6 inches behind the front U-joint. If you don't mind more holes in the floor, it's a good idea to install one in the rear as well. See ...
How do you know when your late-model Mustang needs a driveshaft safety loop? It seems like an easy question, and frankly it really is. Driveshaft safety loops are required by most sanctioning bodies ...