Thicker oil....
try that and see if it gets LOUDER.
LOL......

 

There have been a few people in this thread that have suggested to measure pushrods to correct this issue. This was not a pushrods length issue at all. The rocker was clearly not centered on the valve tip. The issue with the rocker not being centered needed to be corrected before anything else. Now that it is straightened (it should have been properly checked) the pushrod length should be checked. I would never put a rocker arm on without checking pushrod length, it is just too easy. On a non adjustable rocker system pushrod length only determines preload. On an adjustable rocker system, pushrod length will also determine wipe pattern on a properly setup rocker. Pushrod length will never move a rocker forward or backward on an engine (towards either bumper).