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Either should work but I would go with the second one (fig 24). I don't know the limit but the VSS input may miss pulses that are two short. Mostly guessing on that but I know the interrupts are in use for the injector input so there may be limits to what the VSS input can detect.
The 5 volt source may be a little low for the LM2907. The max voltage is 28 volts. I didn't see a minimum voltage but the performance graphs only went down to 6 volts. I would just power it directly off the battery voltage.
It looks like the low part of the signal may not be low enough for the arduino input so it may be necessary to add a resistor to form a voltage divider on the input. The logic levels required are very low, less then 0.2 volts for low and anything over 1.0 volt is read as high.
When you get the circuit built you can toggle the output to low and read the voltage. If the low voltage is less then about 1.3 volts it can be divided down with resistors. If the low voltage level is higher then that a FET and a resistor can be used to give you a signal that goes very close to ground. A wide range of logic gates could also be used for level matching if that's what you have laying around.
Mike
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