Review on GM Engine Mount Energy Suspension 3.1116R - Clamshell Design by Alex Winnick

Easy installation in old folding case. You really need an old donor motor mount to repurpose a steel clamshell box, and a drill press for drilling old spot welds is much better, easier, and safer than using a hand drill. They transmit more vibration to your car than traditional rubber bushings, but this is a compromise with the strength and durability you get from polyurethane.