The 4.7 is an OHC engine so it shouldn't have rockers. I've had the covers of my 4.7 once to clean them up for paint but that's it. They are a pain to get off too. They aren't as bad as some people make them out to be but I had to remove the A/C compressor and move it out of the way. That made life a lot easer. Good luck finding the problem. Sorry I can't help much. I'll be watching to see how things go.