* Vortec 4.3L V6: This engine uses a pushrod camshaft. This is a simpler, more robust design.
* Vortec 4.8L V8, 5.3L V8, 6.0L V8: These engines also utilize pushrod camshafts.
Therefore, there's no single answer. All engines in the 2004 Silverado 1500 used a pushrod camshaft design.
