No grease or sealant
on the sealing surfaces, the manual says nothing about oiling the threads of the head bolts, which I would take to mean not to oil
them. In practice, I would chase the threads in the block with the appropriate size bottom tap, clean and lightly oil
the head bolts, and use some type of 'never seize' on the part of the bolt in the head, and tighten to 12.4 Kg/m. For studs, same thing except for use of a die on the threaded part of the stud. Don't put much on the shaft of the stud, because when you put the head over them, it will push a clump of it down between the head and the block on top of the head gasket
, which could cause sealing problems later on. If it were me and I could get the studs out I would remove them all, clean them up, and when reinstalling the head put two in dry temporarily to align the head and the gasket, and then neverseize (or whatever) the other two and install them, remove the ones used for alignment and never seize and install them, then tighten the head nuts to 12.4. Detroit used to have something called (I think) International Compound #2 specifically for this, but I don't know if they still do or if it is available in a non-proprietary form.
Lot easier to do it than to write it down...