Best way to seal intake and what gasket?

Believe it or not MOPAR RTV and International OEM are the best RTV sealants out there bar none. I have done Power Stroke Oil pans with other brands and had to re-do them. Never with MOPAR or International. You can put the pans on let them dry and remove the bolts and they will stay on. Be real carefull when removing as not to ruin your part.

And get some bristle discs for your die grinder. Make clean up a breeze