Your ad for the 6.0 LS engine says it is a DOHC.
That is ridiculous and proves you do not know a damn thing about the engine.
It has 1 (as in ONE) camshaft in the valley of the block, AKA a pushrod engine.
NOT a Dual OverHead Camshaft (which means 2 camshafts, 1 overtop of each cylinder head directly moving the valves) which has NO pushrods.