this is a customers truck, I've been doing a lot of work to it for a while now. it had a major manifold leak which made a bad ticking sound. the exhaust is all new with no leaks but I can still hear a ticking sound from under the valve covers. the motor has low miles on it but it sat for long periods of time with no use. the owner really wants it fixed but I'm not really sure exactly what is making this sound. I think maybe lifters, rockers? I have a video I just need to post it some how. any thoughts would be appreciated.