The sump plate on the bottom of the engine is most likely stuck on too, lol. That one is pretty easy to knock free with a block of hardwood and a BFH. When you replace the covers with new gaskets installed, DO NOT put any gasket sealer on them !! That's why they're so stuck on there now, lol. I just oil the new gaskets with motor oil. This "puffs" them up to help them seal and also makes them cling to the surface which aids in the install. But most importantly, they won't stick to the cover or motor, making future removal easy. And since the covers come off easily, usually without damaging the gaskets, you can re-use them at least several times before they're worn out to the point that they start seeping.