What rockers?!?

I have a 1999 Silverado 1500 with the 5.3 L Vortec engine. I bought it with 87000 miles four years ago and now it has 160000 on it. Recently, it has started knocking so I need to replace a rocker. What rocker do I need to buy? I can't find the information anywhere. I'm more into older vehicles and know more about how to work on those, rather than the newer vehicles. I can pretty much rebuild my old 77 Ford 302 with my eyes closed, but I would rather avoid anything difficult with the newer fuel injected stuff. Please help!

I dont understand why you would want to replace rocker arms for a knock. Tick, tap or clatter maybe. I would try motor vac or GM top engine cleaner first. Carbon buildup has been known to cause some nasty sounding engine noise in your year of 5.3.

If you are going to replace the Rockers, I am sure you can get that info from the dealer.

I dont understand why you would want to replace rocker arms for a knock. Tick, tap or clatter maybe. I would try motor vac or GM top engine cleaner first. Carbon buildup has been known to cause some nasty sounding engine noise in your year of 5.3.

Thanks for the advice. I'm not familiar with Chevys, especially new ones. I'll give that a try.