The exhaust rockers are the most likely to contact the stock steel covers. And usually the center 2 on each side. My current combo has Landy rockers under stock covers with only .550 lift and I had to dimple the covers for the center 2 rockers on each side.

Sometimes, just slightly slotting the bolt holes and then spreading the valve covers wider in the middle will get enough extra room for the rockers to clear if they do touch.