6.0 Liter engine are notorious for the manifold bolts breaking! Cost to repair are anywhere from $400.00 to $900.00 per side. You are supposed to pull each head and have the broken bolts drilled out. This company (Kral Auto Parts Store) has made adapters that force pressure back on the manifolds themselves which then puts pressure back on the manifold gaskets forcing the leaks to stop. This was a $160.00 plus shipping cost and a whole lot cheaper then the latter, IE, having problems with manifold bolts breaking,

So, if you are having trouble with your bolts breaking, this would be a much cheaper fix.

Kral Auto Parts Store, @ http://kralautoparts.storenvy.com/