I've gone through this multiple times, heat shields, free replacement mounts, etc.
Nothing worked. I had the headers they recommended and they were coated in black, as preferred apparently.
My opinion, poly locs are a poor design.
The two metal sides of the mount do not touch inside the poly. Imagine no poly at all you could only pull them apart by sliding.
Nice for forces that want to pull the mount apart, however the engine actually twists, or turns, slightly, and the mounts 'sliding' direction is vertical, not horizontal.
This causes the engine to sag on the right side, at first, at least in my case, and easily move on the left side, usually up during driving distorting the poly.
I don't know why others do not experience this issue. I have posted a number of times with pics.
Maybe due to the fact that my poly mounts are in an a-body with a tunnel ram, and when the right mount fails it is very noticeable as the engine hits the hood.
However, the a-body right mount is shared by many models, but the left mount is on the front of the engine, far from the header, and has the same issue.
The only real solution was to drill right through the mounts, insert a bolt with a lock washer, and do not tighten all the way.
