Finally got my car back...

Hey everyone.. Haven't posted much but, have been reading alot of the the threads. I had my engine and transmission rebuilt in the Duster, had the 318 warmed up a bit. Amazing how the sound of stock engine with headers and dual exhaust goes from nice and loud, to deep and serious after new pistons and a nice cam to make it lower still and throaty..The car is just for cruising, but man does it sound healthy. Took it for a drive and parked it back in the garage, after about 10 minutes I started seeing anti-freeze in a small puddle on the right side of the car. Process of elimination looks like the last Header bolt is leaking? What does anyone use to seal the bolt? I thought the last hole in the head or second to last was actually into the water jacket yes? Any guidance would be appreciated..
Side note, went to the Mopar Nats, enjoyed it all! But as my luck had it I ordered a FABO T-shirt so I could meet some of the members from here. But as my luck would have it the shirt came in on Monday the day after the Nats.. "day late and a dollar short" seems like my life-long montra!