Mopower Garage

When it comes to the heartbeat of any internal combustion engine, the camshaft is one of the most critical players. It controls the timing of your intake and exhaust valves—essentially dictating how your engine breathes. Over the years, camshaft design has undergone some serious evolution, improving performance, reliability, and ease of maintenance. Let’s take a ride from the old-school solid flat tappet, through the classic hydraulic flat tappet, and into the modern world of roller cams.

Solid Flat Tappet: The Old-School Workhorse

Once upon a time—think cars from the 1910s and ’20 to the muscle cars and drag strips of the ’60s and ’70s—the solid flat tappet camshaft was king. These cams rely on lifters with flat bottoms and no internal oil cushion. They require a manual lash adjustment to maintain proper valve operation.

Pros:

• Perfect for high-RPM, high-performance applications.
• Simple, direct, and aggressive.
• Great for race engines where every thousandth of an inch matters.

Cons:

• High maintenance: You’ll need to periodically adjust valve lash.
• Not forgiving if neglected—premature cam wear is common.
• Requires high-zinc oil (ZDDP) to prevent lifter and lobe damage.

These cams are still alive and well in vintage builds and some drag racing engines. But for street use? They’re a bit of a chore.

Hydraulic Flat Tappet: The Everyday Hero

As car makers sought more street-friendly options, hydraulic flat tappet cams became the go-to. They look like solids, but the lifters are filled with oil and self-adjust for valve lash—no shims, no feeler gauges, no problem.

Pros:

• Low maintenance and quieter.
• Ideal for daily drivers and mild performance builds.
• Affordable and widely available.

Cons:

• Limited in high-RPM performance—hydraulic lifters can suffer from valve float at higher engine speeds.
• Still vulnerable to cam lobe wear, especially with modern low-zinc oils.

For decades, these cams powered millions of engines—smooth, quiet, and easy to live with.

Hydraulic Roller: The Modern Muscle

Enter the roller cam—the big upgrade. Instead of a flat tappet riding the cam lobe, you now have a roller wheel. This reduces friction dramatically and allows for much more aggressive cam profiles without the durability tradeoffs.

Most modern roller cams use hydraulic roller lifters, combining self-adjustment with performance.

Pros:

• High performance with low friction.
• Can support faster valve events and higher lift.
• Much less wear on the cam and lifters—no more flat-lobe failures.
• Long-lasting and virtually maintenance-free.

Cons:

• More expensive, especially for retrofits in older engines.
• Heavier valvetrain components can limit RPM if not matched with upgraded springs and pushrods.

If you’re building a modern performance engine or upgrading a classic, going roller is the smart move—especially with today’s oil formulations.

Camshaft Evolution at a Glance

Type	Maintenance	Max RPM	Durability	Cost	Best For
Solid Flat Tappet	High	High	Moderate	Low	Vintage race engines
Hydraulic Flat Tappet	Low	Moderate	Moderate	Low-Mid	Mild street builds
Hydraulic Roller	Low	High	High	High	Modern performance builds

The Bottom Line

Choosing the right camshaft isn’t just about horsepower—it’s about how you use your engine. If you’re restoring a numbers-matching classic or heading to the strip, a solid flat tappet might make sense. Want a streetable cruiser with occasional track days? A hydraulic flat tappet can still hold its own. But if you’re going all in—whether it’s modern performance, EFI tuning, or you just want to set it and forget it—a hydraulic roller is tough to beat.

No matter what your choice, just remember: the camshaft is the soul of your engine. Choose wisely, and it’ll reward you every time you hit the throttle.