Timing
 

The Ford F-150 I bought new in 1993 finally needed a new distributor & ignition module (350,000 miles). I placed witness marks on the old distributor before removing it placing the new distributor about the same location. The truck starts quickly and so far haven't noticed any roughness. Bought a timing light today but have never used one. Any advise how to check for proper timing and should it be 10 degrees when idling?