If you are using a timing set like the popular Cloyes Hex-A-Just this step isn’t necessary. Fry uses a standard timing set and to build in some adjustability, he drills out the mounting holes oversized ahead of time. The timing gear has already been installed but the bolts left loose. Now, he uses a screwdriver to adjust the timing so that lobe lift matches the cam card. The card lists valve lift, and since Fry is measuring lobe lift he must divide by the rocker ratio. For example, if he is running a 1.5:1 ratio rocker arm and total valve lift at 22 degrees is 0.050-inch, then Fry sets adjust the timing until the lobe lift is 0.033-inch (0.050/1.5=0.033).