So...... you've inspected timing chain dampeners after using 90# springs? It's not like this is the first time this has come up. Many individuals and vendors have noted more wear on the timing chain dampener due to springs with higher spring rate than stock. That's why a lot of people chose 105# springs over the 90's. 90's have stockish seat pressure but higher spring rate. 105's have stockish spring rate but higher seat pressure.