Test your tachometer on any GM car from 1975-1991 that uses a distributor signal for operation. This signal generator will allow you to either bench or car test your tachometer. Attach this to your tach and instantly see 700, 2000, 3000, or 4000 Rpm’s on the tachometer. This test tool will include instructions. Nicknamed after our other famous test machine "Franken Meter".