Manifolds are taken on and off every day,just take your time and do it with the shop manual instructions it will tell you the right way to remove and install them,just make sure that they are straight before you paint them ,put a straight edge across both of them that way if they are not you can take them to a machine shop and have them ground flat before you paint and try and install if they're not straight they will leak or worse crack when you go to tighten them to the block.
Good luck,Pete