The fight between pushrod (OHV) and overhead cam (OHC) layouts is older than most engines on the road, and both sides have legitimate engineering arguments. The difference comes down to where you put the camshaft and how you get motion to the valves.

In a pushrod engine, the cam sits in the block, down in the valley between the cylinder banks (on a V) or alongside the crank (on an inline). The cam lifts a lifter, which pushes a pushrod up through the head, which rocks a rocker arm, which finally opens the valve. That's four moving parts per valve event, and the whole stack has measurable mass and elasticity.

In an OHC engine, the cam sits directly on top of the head, acting on the valve through a bucket, finger follower, or short rocker. Far less reciprocating mass, far less flex in the system.

Why pushrods refuse to die:

• Compact packaging — one cam in the block instead of two or four on top. A Gen V LT1 V8 (6.2L, 460+ hp) physically fits where a DOHC V8 of the same displacement simply will not.
• Lower mass and height — better center of gravity in cars like the Corvette.
• Cheaper to manufacture — one cam, one timing chain, simpler heads.
• Excellent low-end torque due to long intake runners and effective port designs.

Why OHC dominates everywhere else:

• Higher RPM ceiling — less valvetrain mass means less valve float. A pushrod V8 typically taps out around 7,000–7,500 rpm; a DOHC V8 (Coyote, S65) happily spins to 8,250+.
• Independent cam phasing — DOHC lets you advance intake and retard exhaust independently for variable overlap. Pushrods get one cam, so intake and exhaust timing move together.
• Four valves per cylinder is geometrically much easier with two overhead cams.

Rule of thumb for valvetrain mass: Effective reciprocating mass at the valve roughly equals (valve + retainer + spring/3) + (rocker mass × ratio²) + (pushrod + lifter). The rocker ratio squared is the killer — a 1.7:1 rocker makes its own mass count as 2.89× at the valve. Pushrod systems pile on that pushrod+lifter mass that OHC engines simply don't have.

Real-world example: The LS7 (7.0L pushrod) makes 505 hp at 6,300 rpm. The Coyote 5.0 DOHC makes 480 hp at 7,000 rpm. The LS7 produces more torque earlier; the Coyote breathes harder up top. Both are correct answers to different questions.