A meter like the Kent-Moore Tach and Time, Snap-On MT480 or MT1480 will allow pulse or luminosity probe timing. Lumy timing is a bit more difficult as you need to know the cetane number of the diesel you are using.
Since these meters are hard to come by, others use a Ferret adaptor and a timing light.
All will get your truck timed correctly, but pulse, lumy, and ferret are all a bit different and require a bit of trial and error to figure out. However, pulse timing (to me at least) seems to be the simplest way if you have the right equipment.
Heath