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Ben, those are great drawings and you raise many interesting points. It gets more complicated yet when you factor in rocker arm geometry... the rocker supposedly multiplies lift by 1.5, but it does not do so linearly -- it has more "gain" in the middle of the lifter stroke than at either end. Also, that 1.5:1 ratio changes with the position of the adjuster screw -- the further down (tight) the screw is, the lower the ratio.
The lifter in your example D is not an advantage, I don't think. With a flat lifter (they are almost flat in real life), the acceleration of the valve is faster coming off the base and slower approaching the peak of the lobe, as your curves show. This is GOOD. There is also little metal-to-metal contact area during the time the lifter is under the most load, so friction and wear is much lower than with the altered lifter shape -- on the base circle there is lash and so no load on the lifter, and at the peak the valve is decelerating and unloading the lifter (which is valve float if it unloads completely).
Modern cams that have more area under the lobes, and therefore steeper slopes / faster peak velocities, have a ramp coming off the base circle so the valve train is subject to less sudden acceleration, but nonetheless opens to substantial lift faster than with older designs. According to B20B Paul, the OE cams do not have this feature. (???)
Now let me restate what John Parker pointed out several times in the previous thread, because he's absolutely correct: the "optimum" cam is whatever works together with any particular ports, valves, intake system and exhaust system (etc.) to produce the performance characteristics desired in that individual car. A change in any one of those variables requires a change in the cam profile. There are two or three combinations that are proven to work together, and if a customer wants something different, it's a custom job.
This, in a nutshell, is why you can't build performance motors buying parts from a catalog.
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