Sometimes a newbie hasn't memorized the firing order for a Chevy V-8 (18436572) and he has a shiny polished aluminum aftermarket intake that doesn't have 18436572 cast into the top of the intake (instead of something useful like the firing order they cast in Edelbrock, or Weiand). So if you label them Drivers Side1 or D1, D2, D3, D4, and P for passenger P1, P2, P3, P4 as you take them off you can get the plug wires back on to the correct cylinder (since no one realy cares where the plugs go on a 83 that has been sitting up ten years as I doubt if they have been indexed to clear a big piston dome). One less thing to go wrong.
When I mentioned changing the fluids the gasoline (or varnish now) is the most toxic thing in that car. It has to be all drained out and the lines flushed to get rid of the varnish build up caused by rotting gasoline. Anytime gas sits longer than six months it goes bad, unless you have a preservative in the gas (I use Sta-Bil on every fill up, and add Sea Foam if it has been sitting up like in my motor home which is only moved once a year every summer).