You can pick up a crank sensor at most auto parts houses (call around first). As far as the guage, it isn't really necessary. If you are installing a new crank sensor, just turn the crankshaft slowly with socket drive on the balancer bolt and watch to make sure the "Hall-Effect" vanes on the back of the balancer's sensor ring intersect the slot in the sensor without making contact. You can use a matchbook cover to set the gap if you want to.