Noisy Tappets

What's a good oil additive designed to silence noisy valve tappets. Got this Ranger which was non-Op for over a couple of years. I'm activiating it. I replaced the oil and when I started the vehicle it started right away. I cycled starting to allow oil to circulate. However, probably due to gummed up lifters, the tappets were doing the "clickety-clack". I'm sure it will clear up as soon as the lifters gets charged with clean oil.

Change the with atf and run for 20 minutes and drain refill with clean oil.