Valve Stem Seals on 93 Grand Marquis

I have a 93 Grand Marquis that has been burning oil recently. It spits out a blue plume of smoke after idling for a few seconds. I read online that if it does it only when I’m idling then its more then likely the valve seals. I looked online and it doesn’t seem too hard to do. I already have everything I need to change them but I was wondering if there were any other things I should consider changing or checking once I start this operation. My car has over 270,000 miles but it still runs like a champ. Any tips on how I should proceed would be very welcome.

http://www.crownvic.net/ubbthreads/ubbthreads.php
Would probably be a better place to post this question.

This is an OHC engine and replacing these seals is a job for a skilled mechanic with the proper tools… Removing the valve springs with the head on the car (after you have removed the cams) is a tricky job…

How is this tricky? I, a Saturday morning mechanic, have done just that with compressed air through a home made adapter installed in a spark plug hole to keep the valves from falling into the cylinders. I have seen here on CarTalk that some will use a bunch of rope stuffed into a cylinder through the spark plug hole and then turning the engine over by hand, of course, until the rope is tightly up against the valve heads.

Intake valve stem seal failure can show up when stepping on the gas after a period of deceleration when higher vacuum draws oil past the failed intake stem seals. This may not show up due to the cat converter burning the oil.