I am at the point of tying everything down and had the same concern because I have a Be-Cool alum. radiator. there is no top mount on mine and the grill shell is mounted to the rad. side supports. I decided that the original way was best on the bottom mounts and ordered a stock (but stain. steel) mounting kit. It uses a rubber pad under each side and both bolts have a spring on them for movement. They also are set up for a cotter pin because you don't tighten them down tight. That should help. I am also going to run side mounts simular to the Fink mounts, but just on upper mount until I find out about movement.
Jim