motor mounts

[78 Chevyrado]

They're probably polyurethane. Polyurethane is a lot stiffer than rubber, usually used in performance applications. I had a set in an old mustang I had, and mostly what I noticed is it transfers more vibration to the frame, and to you. Its a step between rubber mounts, and solid metal mounts used in racing. So after that I went back to the stockers and liked them much better. Usually on a daily driver the only thing I like polyurethane on is a sway bar. Good luck!