Keep breaking motor mounts!

[66StangGuy]

ok im done trying to use the stock mounts. second set i have broken in a month. what do you think causes this? is it just the torque or do you think it cound be a heat issue? just asking becuase im looking for a set of poly mounts now and dont want to destroy them too because of the heat from the headers. they are hooker super comps. they do not touch the mount or anything but for some reason i destroy the stock mounts quickly. also for a torque strap what should i use? and where should i bolt it too? i dont want to tear out a piece of my engine bay because it was too weak to hold the torque. ill make something if i just knew the best place to mount it too on the frame and the engine.