I have Percys header gaskets on my car. They makes a reusable soft header gasket. Its thick and crushes down nice. You can use them 8-10 times before they have to be replaced.

Or u can try.....
I havn't tried on a 5.0 yet. But a few motorhomes I have worked on in the past. I have thrown the exhaust manifold gasket away and used rearend grease as a "gasket." Just a good bead all the way around the ports on the head. Then crank the engine, DONT rev it, just let it idle and get up to temperature, then retighten the bolts. Works like a charm on the bigblocks....