ep 8 1999 F250 v10 chasing down ticking noise

1999 f250 v10 Ticking noise comes and goes sounds loudest next to the flex plate, I half ass checked the flex plate I have not pulled the transmission to look. Sometimes is loud sometimes not loud and some times it’s not even there all at 600-1800 rpms in park. Tick goes away above 1800 rpms. Did seafoam blow through treatment, seafoam oil treatment, seafoam fuel treatment. Replaced all injectors and all coils, to eliminate miss fires. Used Calvan 38900 kit for spark plug thread repair, checked headers for leaks, deleted the egr, tuned the ecu with delta force software, checked the valve train, looking for this elusive tick.