Thread: roller tip rockers

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Don, with the short cam you're running, don't worry about it.

Thanks Tech1, good to hear from you! Yes, in my usual nit-picking way I hope to get cooler running, short lift on intake for economy and slightly more torque with the 1.6 ratios on the exhaust. One question, though. Since ultimately the energy comes from the fuel-air mixture, I guess the reason the 1.6 ratio on the exhaust valves gives more torque is due to better cleanout of the exhaust gases from the previous combustion allowing more fresh charge on the intakes???

Don Shillady
Retired Scientist/teen rodder

Yeah Don, most all motors flow better on the intake side than they do on the exhaust side up to a certain point in valve lift. That's why you will often see "dual pattern" designs being used. The grinder will put more duration and lift on the exhaust lobes than on the intakes to try to balance the flow while maintaining a short intake closing point for good low-rpm performance. On a SBC with stock-type heads, a difference of 8-12 degrees of duration with a corresponding increase in lift seems to work well.