Removal of the valve cover will not help much. Are you sure the motor is bad? I am pretty sure than on a Gen II the one electric motor controls both. If you have bank 1 stuck and not the other it may be a different problem.
This is not exactly for a Mark VIII, but its good reading:
http://home.flash.net/~ivc1/cobra/imrc.html
But before you venture there I would recommend the proven SeaFoam treatment. Many have reported its success in freeing and improving IMRC operation.
Every so often I put a can (or two if really bad) into the intake. I would let it enter by removing the brake booster vacuum line at the manifold, if the beauty cover is off its really easy to get too. I would them attach another hose to the manifold port.
BTW do it when the engine is plenty warm and be prepared to produce A LOT of white smoke. The neighbors may freak out a little
I would then pull the throttle cable to make the engine rev up and then let it start sucking it up. Try not to let it stall until the very end. By letting it stall you kinda "coat" everything. If you let it just suck it all up and keep running the SeaFoam is "cleaned" off of all the surfaces and has less time to clean things. Let sit for 15 minutes to 30 minutes and try to start her back up. It probably wont start too easily but it will.
Now take her out on the highway, again your going to make A LOT of smoke for a few miles if the car is really dirty. The dirtier the more smoke is produced. Drive her kinda hard to clear everything out. Make sure you pass 3k RPM sometimes, this will open and close the IMRCs. I also try to rev her when adding the SeaFoam to open and close them also.
If you run a second can through you can do it right after the first by not letting it stall and start adding the second can or you can do what I prefer which is to get the first one all cleared out then add the second following the same steps. Normally just one can a year is fine unless you do a lot of city driving.
If I do the two cans I usually get an oil change within 100 miles of the treatment. I dont like adding it to the oil, I feel it thins it. If I do I generally take it easy on the car and get an oil change within 200 miles.
When I first did the treatment above to my Mark VIII I noticed a major gain in the butt-o-meter as well as improved gas milage.