It's just valve train noise. What does that mean?

 

Valvetrain noise is the noise generated from the valvetrain (rockers, pushrods). When you upgrade to aftermarket valvetrain components, they can get noisy. Self-aligning roller rockers are notorious for being noisy. The noises you will hear are the roller tips as well as the rocker roller "bouncing" off the sides of the valve.

 

Thanks Bowtie