Aluminium Frame Mount Pads Problems?

Before I set the 455 engine in my 1967 wagon: I plan to use the T/A aluminium frame pads. Any one have any issues with those?

 

I have a 68-72 set I have never used but they look identical to the cast iron 68-72 and fit the spare set of engine mounts I matched them with.

 

I agree the fit and finish is great, but how are they after years of use? Any failures?

 

Mine are actually in a drawer. I have never used them. They are backups. I know several people have used them and I'm not aware of any failures.