Tomorrow morning, I intend to adjust the valves on my '80 300SD. This will be my first such endeavor, and I have a couple of questions for the experts.

I intend to remove the entire accelerator linkage, after marking all the connections and links. Any handy-dandy tips would be helpful. I also plan on removing the injector lines, so they'll be out of the way, and this is the only thing that makes me a little nervous. Are there "O" rings at the pump and injector ends of the lines that I will need to replace? If so, what size "O" rings should I ask for at the parts counter at NAPA? How tight should I tighten the bolts on the valve cover after I've finished; snug, hand-tight, or tight-tight?

TIA

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1980 300SD 146K miles.