Picking The Right Low
Buck Cam Combination


Words and Photos by Wayne Scraba

What camshaft is right for your car? As you might have expected, there's some good news and there's also some bad news. Let's look at the bad stuff first. Given the overwhelming number of different engine combinations, vehicle setups, usage's and of course, camshaft grinds available, it is virtually impossible to make specific cam recommendations for each and every car, at least within the confines of this article (a book maybe). On the other hand, there's good news too. We've compiled some basic guidelines and generalities that can prove to be immensely helpful in the camshaft selection department.

Before we begin, think about this observation: In a basic high performance car, do you really need a flat tappet roller camshaft? Certainly it's tempting to emulate the Pros, but the overall costs associated with a high rpm, flat tappet roller camshaft valve train coupled with the maintenance program necessary to run such an arrangement might not be in equilibrium with grass roots motorsports. That isn't necessarily bad either. There are plenty of very stout hydraulic roller cams and solid lifter cams along with good old-fashioned hydraulic cams out there (and associated ancillary components). In fact, you might be pleasantly surprised at how much power a mild cam can produce. One more consideration is this: Take a look at the performances turned in by today's NHRA Stock Eliminator cars. Some combinations use hydraulic rollers (late model Camaros and Firebirds are a good example), and plenty more of those drag race stockers use a flat tappet of some sort (hydraulic or solid). And plenty of them run elapsed times deep into the ten-second zone. Granted, some Stock Eliminator racers use trick lifters that act more or less like solids, but many don't. Just as important, those cars are valve lift limited (which makes for some rather unusual grinds). Bracket cars and dual duty street-strip cars aren't.

This is a view of Crane's new hydraulic roller lifters. The benefits include reduced operating friction plus the increased torque and horsepower of a roller cam. A properly engineered hydraulic roller tappet grind produces a broad power band and increased RPM potential with the low-maintenance of a hydraulic cam. Precision check ball internal valving prevents "pump up". Meanwhile, the bodies are CNC machined and assembled with a special "anti-rotational guide bar" design where applicable.

Pressure Tactics ...

Even if you choose to go with a less exotic hydraulic cam, you still have to deal with the selection process. After deciding upon the camshaft type, the next item that you should consider in any engine package is cylinder pressure. While you may have never given this any thought, the camshaft is an integral component in the combustion process. In the heyday of the Detroit-built muscle car, compression ratios ranged between 10.5:1 and 12.5:1. A typical racecar can feature compression ratios in excess of 14:1 while many professional class drag cars (normally aspirated) feature static compression ratios in the area of 16:1. Generally speaking, a lower compression ratio street-style engine can easily use a camshaft that produces more cylinder pressure without fear of detonation. If this very same camshaft is installed in a powerplant with a high static compression ratio, the chances of experiencing severe detonation are increased manifold. In contrast, if a camshaft that is designed for use in a high static compression ratio engine is installed in a low C.R. "emission" or super low octane pump gas motor, the engine will simply roll over and die. Throttle response will be soggy and so will the power output.

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