head gaskets!!

[Koreanese]

when i remove the head, i have to losen the bolt that holds the rocker arms in place so i can piviot them out of the way. then i have to remove the push rods so i can get the heads off to put on new head gaskets. if i do this, do i need to re tune all the rocker arms and timing stuff? cause im planning to do all this by myself and im wondering if i have to adjust anything at pro mechanic shops. plz help me someone
oh yea, do i have to replace intake manifold gasket and exhaust manifiold gasket too if i replace head gaskets?
thank you