You guys are ahead of me, I built my MS2 almost 2 years ago, & still haven’t installed it, but did the mod for sequential, & have plans to install it at some point. I do have a 60-2 wheel on the crank pulley & it's installed w/sensor, but still have to do my cam sensor. I’m all for drilling front cover, I have a few extras in case I mess up the 1st time, but the sensor I have is similar to the one pictured. It has that little O ring, so it can’t leak, right :-) Had thought of bolt on approach to the cam sprocket & maybe just weld a small bolt on top of 1 of the cam sprocket bolts, & trim it so it comes close enough to the VR sensor for a strong signal. It won’t be a balance issue, right ? This is just a street car, not a race motor.
I also kept thinking the fuel pump rod would be perfect, no worries of oil leak, no drilling front cover. You need to use VR sensor instead of hall effect, since it is is not a clean on/off pulse like a tooth would be, but as mentioned it is an eccentric, gradual rise & drop. The VR circuit will spit out a pulse from that, it may be clean enough to use as is. If I remember right from the MS2 forums I asked a while back & MS is only looking for the leading edge from the cam sensor, so a long pulse (duty cycle) may not be a problem.
IOW, that pulse can start before # 1 fires & not end till after # 2 fires. You need to build another LM1815 circuit for MS2 for the cam sensor. I squeezed one into the proto area, but now you can buy a PC board for cheap that lets you build 2 of those circuits.
If a long pulse is a problem, my only other idea was to make a rocker arm type of pivoting lever driven off the fuel pump rod, that in effect ‘shortens” the distance it travels each time around, making a ‘shorter’ pulse, possibly useable with a hall effect. Don’t forget a spring would be needed to keep the fuel pump rod in place. The other thing is MS expects that pulse right before cyl 1 fires, so check on the fuel pump lobe & see where its at, in relation to cyl 1 firing/TDC. Then you realize you almost have to have a lever or some other mechanism to “tune” where the lobe happens. Or you could build a one shot circuit to stretch the pulse also, but then it is no longer a simple mechanical approach.