[impaloligist]

Dealing with my old cars, I would service the trans too. Remember to run through all the gears manually while it is up on jackstands. Not too fast just enough to get it to shift. This will help to get all the clutch packs wet again. Also, pull the rear drums to check if the axle seals went bad. I have has them stick to the axles and were destroyed upon driving for the first time. Now is the best time to find out. If they need replacement, then it would be a good time to service the rear end. Better safe than sorry, pay particular attention to your brakes, as you said that the pedal is low. Brian Hynes has got you covered with the engine, he has a lot of experience with the GNs. Good luck and let us know how you make out!