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Good discussion on cams, especially that the cam has to go with the rest of the engine, but a couple of things have not been mentioned yet.
None of the published figures on cams tell you anything about the shape of the lobe. Two cams with exactly the same published specs can be entirely different
in reality due to different lobe shapes.
Most cams available for B18s/B20s have the same duration for the intake and exhaust. Due to a poorly shaped exhaust port these engines benefit from more duration in the exhaust than in the intake. You can experiment with this by
putting rockers with a higher ratio on the exhaust than the intake. We play with this on the dyno as we can change the rockers in about 1/10th the time of changing a cam.
In today's world there is no reason for a car owner to have to go around trying to select his own cam based on those that are sitting on suppliers shelves ( some have been sitting on those shelves for 20 years). Cams are now computer designed and ground. Doing a one off to match your particular engine is not a problem. It will cost about $100 more than the typical aftermarket cam, no more than some, and takes 3 - 4 weeks. A different intake, different exhaust, different CR, ported head, larger than stock valves, different rear end gearing, are just some of the factors that would go into deciding what cam might be best for your application.
As to high ratio roller rockers. We are not right now offering them as a kit. It will probably be several months before the kit goes back into production. But if anyone wants the individual rockers, we have them.
John
VPD
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