NEW engine is skipping

Freshly rebuilt engine has a skip. Car has headers with duals all the way out the back. I can put a dollar bill at either exhaust tip and the exhaust is pushing it outward as well as trying to pull it in. The heads were completely redone with new valves and the works. I am thinking either I have the valves too tight or burnt valves.
Also, I adjusted the valves according to the Hughes engines chart ( using their rocker arms ) and tightened 1/2 turn after the slack was taken out of the pushrod.

:banghead:

HELP HELP