All we did was upgrade the intake, cam, heads, and valvetrain. The engine was in perfect working order before we did the upgrade, but we noticed the tick right away after idling the the motor down after cam break-in.
The problem must be in the parts/areas that were changed out. If need be I'd change them all out one at a time if a visual of all of them (heads/intake/cam/valvetrain) reveals nothing obvious