head bolt thread sealant?

on the 3.1 it calls for rtv sealant on the head bolt threads and under the heads? i was told this is not really needed is this true? if not what is the best sealant to use i know trying to decide between the 10 million different rtv sealants is a challenge in itself

If it calls for it, its needed.

I usually go with Permetex High Temp RTV silicone. I think it is the stuff in the Red tube. I think the Black stuff might also work, but the Blue if I remember right is for things like differential covers where excessive heat isnt an issue.