"Often someone will use a computer desktop engine program to select the 'perfect' cam specs that has some combination of a big intake, a small exhaust, or really wide lobe separation. Going off the beaten path may be necessary in the long run, but start with something known that can win races. Then go for the experimental parts later. Going the other way around can lead to serious confusion as you try to figure out which unique component of your combination is giving you fits on the track."
Tores doesn't like "tricks," and made that point pretty clear. "Keep it simple," he says. "Save the tricks for later. Allow some room so that other things can be tried, such as different rocker-arm ratios. Don't go out and buy the latest 'trick-of-the-week' combination. Durable parts are more important. If nothing fails after a period of racing, then new components can be tried, following a scientific method of analysis."
Even more to the point, Griffin says, "Listen to the old guys. Go conservative but ask questions about what people have done to really screw things up. If some people don't want to respond to your questions, go ask someone else because the non-responders might not have any real answers anyway." Simple enough.
What is the value (or lack) of lightweight valvetrain components? If there is value, which parts provide the greatest benefit? Multiple pieces of information here, although the perspectives vary slightly. Godbold has this to say: "The closer to the valve, the better your money is spent on lightweight components. Stiffer is almost always more important than lighter as you get to the pushrod and camshaft core. Rockers also typically like stiff just as much if not more than light. Get the valve as light as possible and the pushrod as stiff as possible and work out a good compromise everywhere else.
"Heavy stainless steel valves with steel retainers and standard five-sixteenths-inch pushrods make one of the hardest valvetrain combinations to control at high rpm. The heavy valve system increases pushrod flex (it acts like a spring). When the pushrod springs back, it can surge the valve and valvespring. Then, when it comes back together on the closing side, the pushrod can flex again, resulting in the valve closing well before the tappet gets to the 'soft' part of the closing ramp where rates are controlled. Heavy systems are greatly limited to how hard you can push the components, both in terms of rpm and aggressiveness of useable profiles."
And then, according to Griffin, "Components that will benefit from weight reduction are the valve, retainer, locks and even the spring. The rocker arm benefits from having a lower moment of inertia (where 'lighter' on a weight scale doesn't imply a lower moment of inertia) and a stiffer body. Pushrods benefit typically from having stiffer bending properties, a result of larger diameters, tapers and thicker walls. Another aspect of pushrods that has been examined a small amount is the bending natural frequency which can be increased by making the diameter as large as possible and the wall as thin as possible. On this, little testing has been done to support any theories."
Finally, Tores concludes with these thoughts: "Lightweight valvetrain components are very important. But always remember that you have to be able to finish the race in order to win. So, durability is equally important.