Chevrolet: 1993 Chev Camaro Z28, chev camaro, proform

Question
I trying to install an after market tach(PROFORM) and I  can not find where to connect the wire thst supplys the actual RPM signal....the engine is the LT1 350

Answer
Mike;
   you should have a  neg  and the last goes to the coil  .it should go to  neg, but have some one watch the tach  and the other person touch the wire to see if it works  if yes than bolt it down if not  try  the   other  coil  just touch it  ok. SORRY  it should  go to the NEG  on the coil the ( NEG )   ok