[lukecp]

Wrap teflon tape around the temp sending unit to seal it up. I usually wrap it around the fitting about 3 times, and it provides a nice leak-free seal.

I would put sealant on all the head bolts, but not silicon. Use a copper sealant, perferably the kind that comes in a little bottle so you can dip the bolt in the bottle and thread it in. When i swapped my heads i used a copper selant in a spray can, Permatex Ultra-Copper i believe. It workes pretty good.

On the lifters, if you didn't change cams or anything, just leave them alone.