Update: Randy at RPM figures it should work with up to a 1/2 inch travel. Second option is dual magnets, which is easiest to do next. Just bolt another collar to the first one with the magnets side by side. For starters I will put it on the edge at rest like in the first photo and it should be in range the whole run. Now if my new cam shows up tomorrow like FedEx says, I can finally start putting the motor together and in the car for a test.